So I'm writing a story online with friends, and Character A, who comes from some alternate world where magic is a Thing, gets zapped into our United States and has to make their own life there. Luckily, another, local character lends them a room, so homelessness isn't immediately an issue, but:
1) Considering Character A has no legal identity, no birth certificate, no social security number, et cetera, what serious issues are they going to have to contend with?
2) What steps, legal or non-legal, could be taken by characters in the story to get rid of these issues, or at least mitigate them?
3) What issues would be mitigated or solved if Character A were to marry Character B, who actually is a U.S. citizen?
One more thing, if this helps: Character A comes from a country in the alternate world that is basically Japan with the numbers filed off, language included, but of course they don't have a legal Japanese identity for our world.
I tried looking for answers myself, but most of the results I found were examples of real people with no legal identity without any clear solutions, and the solutions I could find seemed to rely on such things as witnesses to the characters' birth/childhood (e.g. stuff that wouldn't work if the character were from an alternate world).
Thanks in advance.