Just finished a game with these classes and had an absolute blast. For balance feedback the only thing I have is the Speedster perk (which is the same as Grimy's Loot's Superior Sidearm Holster) is very, very powerful. I never chose a different Major perk for a single soldier it was so powerful. My thoughts would be to make it an active ability and give it a cool down.

Edit: I had another thought. The original class has Speedster as a GTS perk which limited it to only the Fury class - that could work.

You might wonder why I think this ability is game breaking as is. There are a couple of reasons but the most basic one for me is that it obsoletes Sparks, MECs and even hero classes to some extent because they can't receive this perk. By mid to end game these units seriously lag behind in battle forcing you to move all units at their slower pace and in addition the lack of an extra action point makes them far less valuable in combat. Taking them along is actually a bad choice. Knowing that, why use them at all?