I need some help...

I really want the trophies in this game (I'm a bit of a trophy hunter). So, I'm gonna buy legendary. But, I have some questions. I already have a level 30 character. He's mentored by Superman, so will I get the trophy for having a level 30 mentored by Superman? Or will I have to get another character mentored by Supes to level 30?

This question applies to other trophies (Platinum race, level 10 Tank and Controller, etc). Basically, the question I'm asking is - If I did the requirements for a trophy, then bought legendary, would I get that trophy instantly? Or would I have to do the requirements for the trophy all over again while I have legendary. Also, do you keep the trophies once your legendary subscriptions runs out?