The Idea: what if marvel owned the fantastic four from the start and got to use them in the mcu, and made films about them instead of the GOTG
Changes: no GOTG trilogy, the F4 take the place of guardians in non solo appearances (such as in avengers), no fox F4 (2000's or 2015)
Technical Details/Dates: 2014 release, filmed in 2013
Misc. Details: Reed and Sue are already dating, they get married at the end.
Description: Four astronauts, including a brilliant scientist named Reed Richards, his future wife Sue Storm, his best friend and the pilot Ben Grimm, and Sue's younger brother Johnny Storm, head into space but chaos arises and they are blasted with cosmic rays, giving them extraordinary abilities, so they form the superhero team known as the Fantastic Four, teaming up to stop the villainous Dr. Doom, a man from Reed's past
Post Credits Scene: Reed perfects dimensional travel, and the F4 travel into another dimension, The Negative Zone