Would I be banned for discussing why I was banned in the past? I'm probably just being paranoid, but just being really careful.

it depends, if you were permanently banned the you WILL be banned sooner or later but if it was a temp ban its ok. :}

I think it depends on what specifically you were banned for. In general I believe the Scratch Team is okay with Scratchers talking about why they were banned, as long as:

(1) such discussion is not disrespectful toward anyone, including the Scratch Team,

(2) such discussion does not repeat the same behavior that led to the ban (e.g. don't say "I was banned for saying [bad word]"),

(3) such discussion is only about yourself, and not about other Scratchers' bans.

But I think I've heard in the past that some Scratchers have gotten banned for talking about their own ban. Perhaps they violated at least 1 of the 3 conditions above when doing so. But I'm not entirely sure.