This is all speculation. These are all hypothetical. Here I put some Avengers characters from the comics and saying how their costumes would look if they were in live-action for a Marvel movie.
Ant Man
Biophysicist and Security Operations Center expert Dr. Henry 'Hank' Pym decided to become a superhero after discovering a chemical substance that would allow the user to alter his size.
Left is a hypothetical costume I found online and right is a cosplay costume of the most well-known comic book costume. Since he is getting his own movie, I imagine the costume will be suped-up and more or less look like the one to the left but not be so full of silver. I think it will be red and blue but a darker hue. Also the mask might look tighter than the left one.
The Wasp
Janet Van Dyne initially a shallow, self-centered, flighty daughter of wealthy scientist. During an experiment, an alien monster was unleashed from an alternate dimension and killed her dad. Her father's associate, Antman convinced Pym to help her.
Left side is a live-action-looking costume and right is a comic book cosplay. I like the use of yellow and black, I think her hair should be short. I think her wings should be shorter and come out later but not always. I like the idea of her costume being all black and tight but I do think she should have yellow gloves and yellow trim on her legs and rest of the suit.
Ms. Marvel
Ms. Marvel initially possessed superhuman strength, endurance, stamina,
flight, physical durability, a limited precognitive "seventh sense",
and a perfectly amalgamated human/Kree physiology that rendered her
resistant to most toxins and poisons, with the added effect of making
her body virtually indestructible. Carol Danvers used to be a reporter and editor of the same newspaper James Jamensson and Peter Parker worked at.
Left is one version of her costume and right is her most-known. I think her costume needs to change for the live-action movie version. I love it in cosplay and in comics, but I think it might look like the live-action X-Men costumes. Look at Jean Grey and Storm that received jumpsuits. Maybe she should have a red belt with the big black jumpsuit, yellow outline bolt on their chest and dark navy elbow-high gloves and knee-high boots.
Scarlet Witch
She is the daughter of Magneto, the twin sister of Quicksilver, The
Scarlet Witch is a mutant who had the ability to manipulate probability
via her "hexes".
Both costumes look similar, but I like the take of the left one that is a corset. I think it should be all red instead of too much pink, maybe light pink. Some people might add black, but Thor doesn't have a lot of black and neither does Captain America or Thor. Well if Captain America can have blue, scarlet and white. Scarlet Witch can have scarlet and red.
Quicksilver
Quicksilver is a mutant capable of moving and thinking at superhuman speeds.I can't find any good costumes for Quick Silver. I like the drawn one above from the comics. I would like to see him in a dark blue jumpsuit similar to the X-Men First Class costumes but with silver in it of course.
Namor
The mutant son of a human sea captain and of a princess of the mythical undersea kingdom of Atlantis, Namor possesses the super-strength and aquatic abilities of the "Homo mermanus" race, as well as the mutant ability of flight. Through the years, he has been alternately portrayed as a good-natured but short-fused superhero, or a hostile invader seeking vengeance for perceived wrongs that misguided surface-dwellers committed against his kingdom.Most cosplays are just nude men with green briefs, a trident and pointy ears. One costume had him with black pants and black open-shirt. I think mos tlikely he won't be shirtless all the time, maybe in one scene or two. I think his ears should be like the recent Spock ears in Star Trek. I think he should have a black and dark green scuba-suit-type suit with a gold belt.
The Vision
The robot Ultron is the creator of the Vision, a type of android he
calls a "synthezoid", for use against Ultron's own creator, Dr. Henry
Pym. he can fire beams of infrared and microwave radiation.
I like the cosplays, but I see him more in a dark green and instead of yellow, a gold. I like to see a golden metal chest plate with the red gem small. Also green boots and small gold gloves. Also his face to be a dark red, a bit like Iron man and Dr. Doom.
Black Panther
The Black Panther is the ceremonial title given to the chief of the
Panther Tribe of the advanced African nation of Wakanda. He eats a
heart-shaped herb which grants him superhuman senses and increases his
strength, speed, and agility to the peak of human development.
I think he should look all armor-like like Batman but not to get mistaken for Batman- have gold trims and the big honky-necklace and big gold buckle and nothing on his chest. Also a big panther-like face.
She-Hulk
Jennifer got exposed to her cousin's gamma-ray Hulk stuff when she had a blood transfusion.
Her most iconic costume is the one to the left with white and purple. For sure, fans would her green skin to show off. Maybe her suit won't be so white and maybe silver with purple trum. I would like a bikini-like costume or maybe an open back.
http://spanengrish.blogspot.com/2012/05/possible-new-heroes-to-join-for.html