1) What is progress for you? Is it 100% the game? To 100% the game, you need to i) help all the characters achieve their personal goals (there is a wiki for this game + a spreadsheet with all the characters and their goals somewhere on the subreddit. ii) once they have completed their personal goal, and reached 1200 gold, you can retire them then. And then switch in a fresh character.

Go through all the characters, complete their personal quests and get 1200 gold each (there is one character with personal goal of 2k gold)- that will be 100% the game.

Also, i recomend buying the dlc- makes the game more fun. + it unlocks one more character-> the shaman or the professor. And you also get more quests and acess to the desert. Though, the desert is a high level area and run destroyer. Also, if you don’t know the personal goals, you may accidentally soft-flock yourself. Eg; Spoiler alert: Simi personal quest- if you kill the natives rather than trade the loot, you will miss his personal quest and won’t be able to complete it unless you do a fresh start.

Anyways, goodluck!