New
#11
Yes - that is what I meant. If you are planning to use Macrium (and I would) then more like this:
Clean and convert disk 0 to GPT
Use Macrium to image Windows Partition (currently on disk 2) to disk 1 (or external drive). No need for system reserved only C:
Make a Marcium recovery disk.
Shut Down
Unplug drives 1 and 2
Set BIOS to boot UEFI
Install Windows 10, boot into it and check you have the correct EFI partitions as per your TechNet link.
Plug in disk 1
Boot from Macrium recovery disk and restore Windows to C partition on disk 0 from your macrium image on disk 1. I.e replace your newly installed C drive contents with the contents of what you are using now.
Unplug 1 again
Check it boots OK
Plug in both other drives again.
Tidy up
Agree with putting OS on SSD. When you do this it will be pretty trivial to use Macrium to move everything on disk 0 to new SSD though if you want to make the move to GPT first.