Talking to non-mahrams

Q: I want to know is it permissible to talk to non-mahrams? Like if someone is studying in a co-education and having boy fellows and male teachers so then is it allowed to talk to them? I have heard that a girl is not allowed to talk to non-mahrams but if in case of helping and if a non-mahram shares his problems with you without having any bad intention so is it allowed? Can girls and boys be friends?

Keeping the names of the Malaaikah

Q: I named my son Mikail. He is now 1 month and 9 days old mashallah. I am confused regarding the name Mikail as people say it is not right to name a child with angel names. I see that there are also people named as Malik (also an angel). I have registered my son as mikail already. I need clarification if I can or cannot maintain the name Mikail (many ways of writing the name also I found but all stand for the same angel). Please help.