In order to grow bacteria, they like the temperature higher. Keeping the temp up is fine. It will help with growth.

(Just make sure your temp is down a bit and steady when you want to add your first fish) As far as the salt...just keep it consistent, if your
LFS will be selling you healthy fish that like that specific gravity, then keep it the same.
Make sure you do have an ammonia source as well, to feed your bacteria! Keep up the good work.