Whether or not it’s viable, it’s extremely problematic to have a ranged cavalry unit that counters light infantry. It defies the game’s rule of thumb that light infantry counters ranged cavalry. Yes, they are actually heavy cavalry, but looking and attacking exactly like light cavalry is just confusing for no reason. That would be like having a unit that looks like a cannon but counters cavalry.
If they’re going to make dismounting be a mechanic, there are only specific roles that can be combined so that the units are balanced.
The theming is also terrible on almost all the dismounting units. Mounted Infantry are extremely generic and have absolutely nothing to do with the Habsburgs. Units that should obviously dismount like Chasseurs (Mounted Riflemen) are poorly named and can’t dismount. Same for the Royal Dragoon that would be another obvious choice to dismount.