Question 1:
Just keep having them repair huts. Yes will take forever. But you only need one after you get all techs to level 3. I have them water the dead flowers

Question 2:
Master Farmer = Strange fish hunt
Master Builder = solving puzzle after you get all your levels up.
Master Scientist = School
Master Healer = they heal people. Also will heal people on their own so you don’t have to find them yourself.
Master Parent = A whole lot of going indoors

Question 3:
Just to annoy you? I think also helps with there health but not sure.

Question 4:
I try a kid or someone the same sex. Just keep picking them up and trying again.