1. Is there a guy that allows you to change the name of your Pokemon?

2. Where is the best place to train that isnt directly involved with the Elite 4? I want to train my 60-75 level pokemon but I dont want to fight the Elite 4 everytime.

1: Yes, there is. The name-rater is in Castelia City, the location of the 3rd gym.
2: Go to places where you can battle trainers daily, such as the stadiums in Nimbassa City, and the Battle House in Opulecid city.