Bow knight doesn’t work for most units, but Leonie’s point blank volley helps a lot. Bow knight Leonie can orko a good spread of enemies while having good mobility and utility. She’ll be solid throughout the game and be a decent player phase unit long term.
Class Path
Soldier or fighter -> Brigand/Archer/Pegasus -> Paladin or Sniper or Wyvern Rider -> Bow Knight
Soldier vs fighter is just str +2 vs reposition. Go with preference. It’s also not hard to get both.
For advanced classes, all three are fine. You can do multiple but none of them are essential. Sniper’s probably the worst but it also lets you rush A bows the hardest.
Rank Priorities
C bows -> C lances -> E+ flying -> D+ axes -> advanced class ranks -> B authority -> A bows -> riding rank for bow knight if you lack it.
When you’re done with these consider A authority, A+ riding, and A+ or S bows. Wyvern lord ranks are pretty good. You can go wyvern lord instead of bow knight if you like.
Skill Loadout
Darting blow doesn’t help with point blank volley, but when it lets you double from range it’s pretty good.
Recruitment
Out of house Leonie should be recruited in chapter 6. Soldier doesn’t give her anything and cav gives a nice bump to her stats.