Those elements just need to be updated, not included. After Infinity War it could be as easy as trying to perfect interstellar travel after proof of hostile aliens with the Chitari and later Thanos.
Only Captain America should go that route as that is a part of his story originally. The FF have always been a part of modern times and being lost in time is not their story and nor should it be.
60s Sue was the worst to the point where fans wrote in about how bad she was. She is definitely a product of the misogyny of the 60s with only being the wife and token girl of the team who was too occupied with material things a lot of the time and that version should never be visited again. Byrne elevating her from Invisible Girl to Woman was much welcomed and needed.
No That is really young and Marvel has only done that age range for Spider-Man. Every other main player in the MCU started out in their mid thirties or early forties.