1940
Stan Lee
Namor the Submariner I don't know who was the first Marvel character, but Namor was the first mutant, not the first character.
Marvel
The Fantastic 4 are Marvel and in 2019 Kevin Feige announced that a Fantastic Film will be in the MCU (Marvel Comics Universe)
The second word in the phrase marvel vs capcom is marvel, mar is the first word
The first super hero of Marvel was Captain America. It originated from Stan Lee's idea, became a super hero of Timely Comics (which was renamed Marvel comics), and was the first super hero produced from Marvel in 1941.
Cyclops and Ms. Marvel
R is before t-so Marvel. (alphabetically)
Thanos is a Marvel character. He first appeared in a Marvel comic in 1973 and has since become a prominent villain in various Marvel comics, movies, and TV shows.
superman
Marvel Comics #1 (cover dated Oct. 1939) .
I am assuming that you mean Ms. Marvel because there is no character in Marvel Comics that is named Mr Marvel. Ms. Marvel's first appearance was in Marvel Super-Heroes #13 (March 1968)
The Human Torch (android) and Namor were the first people to be depicted in Marvel Comics