Surprisingly 4 was pretty easy for me. I'm saying that because I was an extremely shy person at the very start. If I hadn't gone to uni things would've definitely been hard for me.
Regarding 4, I was only successful in making friends when helping them and expecting nothing in return. Attempts at small talk and trying to attend socials were not enough.
I'm starting to think that just small talk and hanging out were enough to make friends in school, but not at uni or real life, for some reason.