I agree with the 1st part, that would actually make sense and is the time travel you normally see in TV & Film such as The Butterfly effect, Hot Tub Time Machine, DBZ, etc. Going into the past and making changes effecting the future.Even if Hodor lived a normal life before Bran warged into him, once Bran did that the past was altered which is the storyline we're currently seeing.
Say that scene in Winterfell played out before with Bran not warging into Hodor and everything was "normal", once Bran had that vision and warged into Hodor while basically stuck in between the two timelines the past was forever changed so that the people around Hodor, and Hodor himself, only know that outcome. Hodor was basically living only to "hold the door" and save Bran.
IMO, he should have been normal up until Braun went back in time and caused his issues. Otherwise makes no sense unless there is another alternate timeline.