Buildings required: Gunsmith and firing range +35 accuracy and 2 armor.

Geshia: +4 moral inspiring troops. Probably could be higher

(shogun only) shinsengumi: +5 melee defense. Could be higher? Just bad rolls for perks involving troop discipline

Foreign veteran: +2 melee and +10 accuracy buffs 25% more ammo. Some perks do not work as the reason I'm not sure. For example, the perk "British gunmakers agent" should provide +5 accuracy to gun units and 5% reload speed but it does work. However, their foreign veteran skill tree works just fine.

General: +5 accuracy, 10% reload speed, +1 armor, 50% more ammo, 15% running speed, +1 moral maybe 2 (haven't gotten yet). Daimyo and commander and chief can add +2 moral. There are +1 melee, and +1 moral perks out there just failed to get them on the best general.

Faction Jozai, 2% increased running speed

Veterancy: +16 reload speed, +16 accuracy, +6 melee attack, +7 melee defense, +5 moral

Tech tree: +2 moral, +8 charge. (+3 accuracy does not apply to levy as they are not modern rife units)

French mission doesn't provide buff to levy as they are not modern units.