It is already implemented as Northern Musketeers and the historic use of the Opolcheniye was far more extensive than what the militias at the Town Center are supposed to represent.
Every visual indicator screams musket infantry. They carry a big melee weapon and use the same pose as musketeers. Frankly, it’s kind of weird and unintuitive that they aren’t musketeers.
The Counter-Dragoons don’t have a unique skin, they look exactly like normal Dragoons. There’s absolutely zero reason to retain these units.
This could be a good way to retain the new Jaeger skin, it’s a synonym for Lifeguard anyways. The Leib Guard included a whole range of units, so this unit could be given the dismounting ability to utilize the currently unused mounted variant. It seems like that was the original intent, but they would have realized that a light cav/counter-skirm is a bad idea because it hard counters its counters just by dismounting. You have to pair unit types with the same counters like light cav/musket infantry or heavy cav/counter-skirm. To preserve their current role, Leib Guards could be heavy cav/counter-skirm since linking counter-skirms to the dismounting ability would solve a ton of problems.
Is there any reason these must have firearms? Maybe it could be an alternate name for Poruchiks.