For the late departure at least the TSA check to go to the BA flights was pretty quiet so the lack of any dedicated Pre-check lane etc shouldn't be a big deal .. took only a few moments to get through ... perhaps the earlier departure might be a different story

Lounge is fine, a little dated but fairly large .. nice big windows with a view over the airport and the food offering is really quite good ... it's upstairs on your right just after security .. I guess the new AA lounge in the new terminal is going to be nicer, but the BA one is perfectly fine .. definitely no reason to change terminals to avoid it given that's impractical at Newark !