Like I've said on other boards, I'm adapting a text roleplay: basically a book written by two people, where one person controls each character. Well, the friend I wrote it with has the entire file, but part of mine got deleted, and said part is the very beginning.

I'm just writing a basic guideline of what I know happens there, but what should I do for dialogue? Make up something that the characters would actually say, since it's an adaptation anyhow? Or should I just red-flag it and put the "real" dialogue in later?

Also, that section includes a MAJOR plot point. Should I skip that and add it in later once I have the file, or fudge it?

Maybe ask the friend to send you the entire file? Otherwise, try and rebuild it or just skip past that part and write the rest. This is only a draft, certainly doesn't have to be perfect.