Officejet 6600 Scanning Fails in Fedora 27

I recently installed the Fedora Design Suite Distro, Version 27. The printing on my Officejet 6600 works, but the scanner, either using Simple Scan or Xsane, does not (scanner is not found). I have run hp-check -t, and found:
HP Linux Imaging and Printing System (ver. 3.17.11)
Dependency/Version Check Utility ver. 15.1

Copyright (c) 2001-15 HP Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.

Note: hp-check can be run in three modes:
1. Compile-time check mode (-c or --compile): Use this mode before compiling the
HPLIP supplied tarball (.tar.gz or .run) to determine if the proper dependencies
are installed to successfully compile HPLIP.
2. Run-time check mode (-r or --run): Use this mode to determine if a distro
supplied package (.deb, .rpm, etc) or an already built HPLIP supplied tarball
has the proper dependencies installed to successfully run.
3. Both compile- and run-time check mode (-b or --both) (Default): This mode
will check both of the above cases (both compile- and run-time dependencies).

Check types:
a. EXTERNALDEP - External Dependencies
b. GENERALDEP - General Dependencies (required both at compile and run time)
c. COMPILEDEP - Compile time Dependencies
d. [All are run-time checks]
PYEXT SCANCONF QUEUES PERMISSION

Status Types:
    OK
    MISSING - Missing Dependency or Permission or Plug-in
    INCOMPAT - Incompatible dependency-version or Plugin-version

warning: 5-27 version is not supported. Using 5-26 versions dependencies to verify and install...

---------------
| SYSTEM INFO |
---------------

 Kernel: 4.14.8-300.fc27.x86_64 #1 SMP Wed Dec 20 19:00:18 UTC 2017 GNU/Linux
 Host: localhost.localdomain
 Proc: 4.14.8-300.fc27.x86_64 #1 SMP Wed Dec 20 19:00:18 UTC 2017 GNU/Linux
 Distribution: 5 27
 Bitness: 64 bit

-----------------------
| HPLIP CONFIGURATION |
-----------------------

HPLIP-Version: HPLIP 3.17.11
HPLIP-Home: /usr/share/hplip
warning: HPLIP-Installation: Auto installation is not supported for 5 distro 27 version

Current contents of '/etc/hp/hplip.conf' file:
# hplip.conf. Generated from hplip.conf.in by configure.

[hplip]
version=3.17.11

[dirs]
home=/usr/share/hplip
run=/var/run
ppd=/usr/share/ppd/HP
ppdbase=/usr/share/ppd
doc=/usr/share/doc/hplip-3.17.11
html=/usr/share/doc/hplip-3.17.11
icon=/usr/share/applications
cupsbackend=/usr/lib/cups/backend
cupsfilter=/usr/lib/cups/filter
drv=/usr/share/cups/drv/hp
bin=/usr/bin
apparmor=/etc/apparmor.d
# Following values are determined at configure time and cannot be changed.
[configure]
network-build=yes
libusb01-build=no
pp-build=yes
gui-build=yes
scanner-build=yes
fax-build=yes
dbus-build=yes
cups11-build=no
doc-build=yes
shadow-build=no
hpijs-install=yes
foomatic-drv-install=yes
foomatic-ppd-install=no
foomatic-rip-hplip-install=no
hpcups-install=yes
cups-drv-install=yes
cups-ppd-install=no
internal-tag=3.17.11
restricted-build=no
ui-toolkit=qt5
qt3=no
qt4=no
qt5=yes
policy-kit=no
lite-build=no
udev_sysfs_rules=no
hpcups-only-build=no
hpijs-only-build=no
apparmor_build=no
class-driver=no

Current contents of '/var/lib/hp/hplip.state' file:
Plugins are not installed. Could not access file: No such file or directory

Current contents of '~/.hplip/hplip.conf' file:
[last_used]
device_uri = hp:/net/Officejet_6600?ip=192.168.0.105

[installation]
date_time = 01/01/18 15:45:39
version = 3.17.11

 <Package-name> <Package-Desc> <Required/Optional> <Min-Version> <Installed-Version> <Status> <Comment>

-------------------------
| External Dependencies |
-------------------------

 error: cups CUPS - Common Unix Printing System REQUIRED 1.1 - INCOMPAT 'CUPS may not be installed or not running'
 gs GhostScript - PostScript and PDF language interpreter and previewer REQUIRED 7.05 9.22 OK -
 xsane xsane - Graphical scanner frontend for SANE OPTIONAL 0.9 0.999 OK -
 scanimage scanimage - Shell scanning program OPTIONAL 1.0 1.0.27 OK -
 error: dbus DBus - Message bus system REQUIRED - 1.12.0 MISSING 'DBUS may not be installed or not running'
 policykit PolicyKit - Administrative policy framework OPTIONAL - 0.113 OK -
 network network -wget OPTIONAL - 1.19.2 OK -
 error: avahi-utils avahi-utils OPTIONAL - - MISSING 'avahi-utils needs to be installed'

------------------------
| General Dependencies |
------------------------

 error: libjpeg libjpeg - JPEG library REQUIRED - - MISSING 'libjpeg needs to be installed'
 cups-devel CUPS devel- Common Unix Printing System development files REQUIRED - - OK -
 cups-image CUPS image - CUPS image development files REQUIRED - - OK -
 libpthread libpthread - POSIX threads library REQUIRED - b'2.26' OK -
 error: libusb libusb - USB library REQUIRED - 1.0 MISSING 'libusb needs to be installed'
 sane SANE - Scanning library REQUIRED - - OK -
 error: sane-devel SANE - Scanning library development files REQUIRED - - MISSING 'sane-devel needs to be installed'
 error: libnetsnmp-devel libnetsnmp-devel - SNMP networking library development files REQUIRED 5.0.9 - MISSING 'libnetsnmp-devel needs to be installed'
 libcrypto libcrypto - OpenSSL cryptographic library REQUIRED - 1.1.0 OK -
 python3X Python 2.2 or greater - Python programming language REQUIRED 2.2 3.6.3 OK -
 error: python3-notify2 Python libnotify - Python bindings for the libnotify Desktop notifications OPTIONAL - - MISSING 'python3-notify2 needs to be installed'
 error: python3-pyqt4-dbus PyQt 4 DBus - DBus Support for PyQt4 OPTIONAL 4.0 - MISSING 'python3-pyqt4-dbus needs to be installed'
 error: python3-pyqt4 PyQt 4- Qt interface for Python (for Qt version 4.x) REQUIRED 4.0 - MISSING 'python3-pyqt4 needs to be installed'
 python3-dbus Python DBus - Python bindings for DBus REQUIRED 0.80.0 1.2.4 OK -
 python3-xml Python XML libraries REQUIRED - 2.2.5 OK -
 python3-devel Python devel - Python development files REQUIRED 2.2 3.6.3 OK -
 python3-pil PIL - Python Imaging Library (required for commandline scanning with hp-scan) OPTIONAL - 1.1.7 OK -
 python3-reportlab Reportlab - PDF library for Python OPTIONAL 2.0 3.4.0 OK -

--------------
| COMPILEDEP |
--------------

 libtool libtool - Library building support services REQUIRED - 2.4.6 OK -
 error: gcc gcc - GNU Project C and C++ Compiler REQUIRED - 7.2.1 MISSING 'gcc needs to be installed'
 make make - GNU make utility to maintain groups of programs REQUIRED 3.0 4.2.1 OK -

---------------------
| Python Extentions |
---------------------

 cupsext CUPS-Extension REQUIRED - 3.17.11 OK -
 hpmudext IO-Extension REQUIRED - 3.17.11 OK -

----------------------
| Scan Configuration |
----------------------

 hpaio HPLIP-SANE-Backend REQUIRED - 3.17.11 OK 'hpaio found in /etc/sane.d/dll.conf'
 scanext Scan-SANE-Extension REQUIRED - 3.17.11 OK -

------------------------------
| DISCOVERED SCANNER DEVICES |
------------------------------

No Scanner found.

--------------------------
| DISCOVERED USB DEVICES |
--------------------------

No devices found.

---------------------------------
| INSTALLED CUPS PRINTER QUEUES |
---------------------------------

Officejet-6600
--------------
Type: Unknown
Device URI: dnssd://Officejet%206600%20%5B4EA65B%5D._ipp._tcp.local/?uuid=1c852a4d-b800-1f08-abcd-38eaa74ea65b
PPD: /etc/cups/ppd/Officejet-6600.ppd
warning: Failed to read /etc/cups/ppd/Officejet-6600.ppd ppd file
PPD Description:
Printer status: printer Officejet-6600 is idle. enabled since Tue 26 Dec 2017 12:40:43 PM EST
warning: Printer is not HPLIP installed. Printers must use the hp: or hpfax: CUPS backend for HP-Devices.

--------------
| PERMISSION |
--------------

-----------
| SUMMARY |
-----------

Missing Required Dependencies
-----------------------------
error: 'cups' package is missing or 'cups' service is not running.
error: 'dbus-devel' package is missing/incompatible
error: 'libjpeg-devel' package is missing/incompatible
error: 'libusb1-devel' package is missing/incompatible
error: 'sane-backends-devel' package is missing/incompatible
error: 'net-snmp-devel' package is missing/incompatible
error: 'python3-PyQt4' package is missing/incompatible
error: 'gcc-c++' package is missing/incompatible

Missing Optional Dependencies
-----------------------------
error: 'avahi-tools' package is missing/incompatible
error: 'PKG_FROM_PIP:notify2' package is missing/incompatible

Total Errors: 11
Total Warnings: 1

Done.

Above includes fewer dependency errors than the hp-check I ran before because I installed, or at least attempted to install some of them. However, on some trials the packages could not be found, or on some others, the installations completed, but the dependencies are still not reported here.

Suggestions on how I can get my scanner to work? Many thanks!