M.2 GPT UEFI Multi-boot with MBR

Hi,
Just upgrades MB to Z270 motherboard!

I had a multi boot MBR setup that would boot to grup(ver ?) on one drive (disk 1?). From there I could go to Unbuntu, or to a Win MBR boot menu (Disk?). There I could go to any native OS from XP to Win10. Very cool set up.

With the new motherboard, I have those same drives, but I now boot from a M.2, RAID 0, UEFI, GPT drive to UEFI installed Win 10 x64. The other drives are not showing in the BIOS as boot available drives.

I would like to know how to reinstall Unbuntu (if needed), to where it was before, but so that grup is first in control. From there I can go the new Win 10 install, or go to my old MBR boot menu on the old drive as it still is sitting there.

It sounds like I know a lot about this. But NO I Do Not. I know something about this, but nothing about the details of actually doing it. I am a Total novice about command line linux stuff. It took a lot to figure out, with a lot of forum questions, how to install Ubuntu is my previous setup.

From what I've read so far, I think it should be possible to do what I want to do. But I have no idea How To Do It with out screwing things up. I could use a lot of hand holding with this. please.
I have attached a snip of my drive set up as shown from Acronis 12 Disk Director. Unbuntu (latest version) sits at the end of disk 1. I think the system original booted to grup there. But I'm not totally sure. I think the MBR boot menu is on Disk 2 so I could get to XP to old Win10 (on Disk 2)
Also I need some translation from Win disk/partition names to linux; Win Disk 1/XP-MCE 2005 = ????, etc, please help with a list (ps Disk 1 & 2 are SSD's)
The system currently boots from Disk 5.
Yes I have a complete back up of everything. I have nothing on the Linux install that needs to be saved, if a reinstall is the easiest way to proceed.

If some one with some major knowledge about these things could spell out the steps involved in my quest I would be most appreciative !!!

If you need more info to set up a procedure, please ask.

MANY, MANY, MANY Thanks
KLund1