I’ve been mostly through the udpate process. Rear shock that is great is the Cane Creek Cloud 9. It’s 5.5 eye to eye and has 1.25 of stroke. They can custom build you a new one to that spec if they don’t have them in stock. Other Cane Creek rear shocks with those specs will do the trick as well.
I’ve been running a RockShox Reba Team set at 120mm in the front. Great fork, but when I get it overhauled I’ll probably have it set to 100 to have it more balanced. Not that big of an issue. I just swapped my stem position with a few of the spacers to get it to feel just right.
9 or 10 speed is up to you. No limits there. There are lots of 10 speed and 2×10 options that are lower cost than the SRAM XX now.