Marty does get new memories but he doesn't automatically get them after George kisses Loraine. This theory completely contradicts the ending of the film where he's surprised by the fact his whole family is successful and happy. If he already had those memories he wouldn't have reacted that way and been aloof. I don't think he gets them until after he returned to 85 and even then, they slowly start to develop. I've heard they discuss this topic in the comic books. I do agree that him being called chicken is due to the timeline changes though.

Original Marty accidentally changed his future for the better. Second Marty would have to maintain the lifestyle changes OG Marty made so events would play out similarly. 2nd Marty would come to realize he is the "Calvin Klein" that he heard his parents talk his whole life up to that point. I'd also argue that there wouldn't be two Marty's in 1955 because 2nd Marty is in the position OG Marty was in. Only time they'll be two Marty's is when OG Marty goes back in BTTF2 for the almanac.

I'd argue that we don't need a new actor to play a new terminator. I'd say Terminator 7 need to finish what Salvation started and continue with the war and older model Terminators. We don't need ANOTHER time travel movie trying to prevent Judgement Day. Go back to the roots of the original and make it a horror film about the struggles of humanity after the bombs dropped. I'd also say we don't even need it to focus on John or Kyle, a new character is perfectly fine.

Favorite films are T1, T2 and Salvation even with its issues.