I'm just going to answer this question now as im only on 1-6 part 1. I'll give you the rest of my feedback when I complete the current release.
My opinion is that fewer enemies that are more powerful is preferable to a litany of weaker enemies. One of my favorite aspects of FE games is to see that EXP bar go up, and weaker enemies tend to give little EXP and make me feel like that kill was a waste. This is a big problem through a lot of the base FE10 game. I also think that for this particular map, the scenario lends itself to fewer enemies, as Duke Ludveck has taken the majority of his forces to ambush Elincia, and only left a small army to distract the crimean knights. However, this army should still be difficult to combat, with long range spell casters added to the walls to make for a more formidable position. Maybe give the player some incentive to capture both sides of the castle walls rather than just defeating the boss and seizing the castle.
This is just my opinion, but I could also see having a ton of weaker enemies being fun, as it would make for a very chaotic castle siege. I think having a ton of enemies would lend itself better to the 2-E however; im talking like wave upon wave of enemies, making it much more of a defense chapter where you could actually feel like you might lose the position if you aren't careful.
Also, just want to say I am loving this project so far! Can't wait to finish so I can give you more feedback, but it will probably be a few days because of work and school.