Of the NPCs, the Turb Captain, Buttercup, can teach Single Weapon for up to fifteen people.
The Archery Captain, Mairead, can teach Bows for up to ten people.
There are some specialists in the Player-Submitted Points post that can probably train.
Other than that, unless someone wants to slap some grogs together, any other training would be done by either your people or by npcs who can teach one person and wouldn't have a score higher than 5 (not including specialty).
Wealthy characters get 20 xp per year, plus Adventure. Poor characters get 10 xp per year, plus Adventure. Everyone else who doesn't do Seasonal Advancement gets 15 xp per year plus Adventure.