I know I mentioned this before, but playing through all the current content has confirmed that my units snowball quickly, even on "hard" mode. I understand the narrative element where Monster Girls are strictly superior to humans, but it's a bit absurd this early on. I'd reduce growth rates across the board, make it harder for individual units to solo entire groups of enemies. This is how I'd change the growth of the Playable characters. Note that while I have not made an SRPG, I have played every mainline Fire Emblem game besides Gaiden.
Maia: 75% HP, 35% Str, 45% Mag, 45% Skl, 50% Spd, 50% Luck, 25% Def, 30% Res; Total 355. Her growths are all above average aside from HP, a unit with no weakness while not dominating in any one area. I made her magic growths slightly better since she can use all magic types but the only weapon type she can use is lances. I'd also give her an acrobat-type skill (move through all traversable terrain without penalties) since she can use her wings to boost her mobility.
Elise: 90% HP, 55% Str, 5% Mag, 40% Skl, 40% Spd, 35% Luck, 25% Def, 10% Res; Total 300. Classic bruiser type with high HP and Str but mediocre defenses.
Violet: 65% HP, 35% Str, 5% Mag, 60% Skl, 60% Spd, 60% Luck, 15% Def, 15% Res; Total 315. High Skill, Speed, and Luck, but shaky strength and poor durability make her rely on dodging attacks rather than taking them.
Emily: 85% HP, 50% Str, 30% Mag, 35% Skl, 20% Spd, 30% Luck, 50%, Def, 20% Res; Total 320. Very slow but incredibly durable. Will end up being more useful now that not everyone is capable of taking many hits.
Steph: 50% HP, 10% Str, 50% Mag, 35% Skl, 35% Spd, 60% Luck, 10% Def, 50% Res; Total 300. High magical attributes and incredible luck but incredibly frail physically.
Galiena: 70% HP, 30% Str, 20% Mag, 60% Skl, 50% Spd, 40% Luck, 25% Def, 25% Res; Total 320. Relies on Maid Daggers and effective weaponry do deal heavy damage but has enough durability to survive multiple hits from both physical and magical enemies.
Sylvie: 70% HP, 50% Str, 10% Mag, 50% Skl, 50% Spd, 50% Luck, 10% Def 20% Res; Total 320. Absolute glass cannon with high mobility. Her skill will need to be changed, but fliers often go off on their own anyway due to their mobility.
Lily: 80% HP, 15% Str, 60% Mag, 50% Skl, 30% Spd, 25% Luck, 30% Def, 30% Res; Total 310. Reliably hits once for heavy magic damage while, but more skillful enemies may end up landing a critical hit against her doing heavy damage. Her skill should probably make enemies more prone to attacking her due to how big her true form is.