I think that’s a good way of doing it. Considering how important Echo and Fives (the former especially) go on to be they do need to be the focus. It’s good that you’re keeping as much 99 as possible as he’s the clear inspiration for Clone Force 99 and Echo’s part in that.
One thing I find a bit weird (and this is with TCW in general not with these edits) is how ARC Troopers are classed as something to be promoted to, rather than a lighter version of the Clone Commandos. Fives does seem to have earnt some Special Forces bona fides by the Umbara arc but the pair of them in the Citadel arc and Jessie in the SoM arc are basically normal troopers with fancy armour.
The other thing is how much Cody defers to Rex despite out-ranking him. I know they were going for playing down Cody so audiences didn’t get to liking him, but it leaves Cody looking like another trooper in fancy armour.