The Hussar is a more recent unit than knight. I believe this unit start been used in xv, on mercantilism to on.
Knights were from the midle ages.
I believe that you could post they like an upgrade to knight, in gunpowder (nothing to do with the tec, but they are common in the time of the musketmen) 5/3/3. Or better, another unit with 5/2/3.
I use knight as whelled, this unit could be not whelled to increase diference.
Dragoons and cavalry are not supose to be use as same, but are more close to this than hussar and knight.
If you use the regular game stats it will be dificult to made some diference between they two, so, you probably will end using one in the place of other like UU.
Piemonte is in the Italy northwest (turin).
Bachibouzouk is a kind of arab musketsman.
I think is good to Arabia and north african civs.
To babylon and persia, or even others i don't think it's fine.
Luck to put this babes on your game man. Bye.