They wont though, they will go as all musket, then they will get annihilated by cav because of no bayonets, then they will get told they need pikemen, then half will quit saying unbalanced.
So to avoid this, you should really emphasis the need for pikemen.
Well muskets should be nerfed, they should be nowhere near what they are in NW. I am sure the developer has thought of this though, since muskets took much longer to reload, and the accuracy was much, much lower. But it needs to be really rock paper scissor, since Pikemen takes out cav, cav takes out muskets, but muskets can't really take out Pikemen then, well i guess that is where artillery comes in.
I hope musketeers will be auxilliary to pikemen, kind of how in other mods where a line of 20 or so gets a few archers, maybe every 4 guys you get 1 musket or so, i think historically it was 1:6 in the Imperial armies and 1:3 in the Swedish army, but i guess that is up to the event hoster.