1) We don't know if the spider that bit him is radioactive. We don't know the route MCU is taking; most likely, though, they will go with the genetically modified route. But nothing's been confirmed.
2) He isn't a vigilante. He was a neighborhood hero, stopping bike and car thefts and helping old ladies cross streets. He wasn't hunting down criminals - only time he ever decided to do so was to apprehend Vulture, and that was to impress Stark and become an Avenger. Meaning he wasn't a vigilante juggling civilian and alter ego life when Stark found him.
3) "is an American superhero" part is something other pages don't have, ex. Cap or Stark, or Hulk, or literally anybody else. It's not something the wikia as a whole does therefore for consistency's sake, it had to go.
There is no official confirmation from neither Marvel Studios nor Sebastian Stan about the Winter Soldier appearing in Avengers: Infinity War. Until they say something, everything else is just speculation, and we don't allow speculation in our articles. Is that clear?
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