What would you do with......?

Probably none of them. They did not seem to need any other friends.

What would you do with the Marauders Map? (Let's say it is possible to modify it, so it shows another place)

I think I would use it to avoid all the nagging people .

Would you rather take Hagrid's cake or Polly Juice of Vernon Dursley ?

Vernon Dursley just so I could pester him and see him turn purple! lol

What would you do with a talking llama?

hmm...a talking llama? i think the question here is not "what would I do" but "what wouldn't I do with a talking llama?"

what would you do with the Horcruxes (after they've been destroyed)?

Restore them, if possible, as they are relics of the founders. If restorable, they'll go in the Head/master/mistress' office. If not, they'll be part of a war memorial. Either way heavily warded.

What would you do with Dumbledore's portrait?

i'd put it up in my house & scare people by having him say things at random times but not let people know it's him saying them; act like a non-moving picture

what would you do with a pot of devil's snare?

Grow it to appropriate size, booby trap something.

What would you do with a niffler?

I dunno...hug him

what would you do with veritasserum??

Force Dolores Umbridge to drink it and ask her why is she so ruthless.

What would you do with Filch?

Use his own chains to hang him from the ceiling.

What would you do with Felix Felicis Potio?