Just sharing that captured Heroes can be "Taken Out" with you on quests via the desk to the right. Each one adds 1 point to your stats. Felicity ("GF") gives you Charm, Locke ("Fox Golem") and the Barbarian ("Forest") gives you Power, Julian ("Circus") and Cleric ("Town") gives you Wisdom. I think the Rogue is bugged, so I haven't gotten him yet.
With a full party and 1 witch's bottle, you have enough to have 1,2,3,4 on your stats, distributed as you see fit, which is enough for all challenges so far. Just need to make the correct choices, and some save-scumming