I know that obviously the bonus for the more expensive versions are disallowed but would enhanced dodge parry assist be banned? Don't want to play a 6 hour run just for it to be invalid.

For lowest difficulty, any combination of accessibility options is allowed, including enhanced parry timing. There was some discussion of potentially banning that for Ultimate runs specifically, but I'm not sure what the final verdict on that was (if that was meant to be banned, the leaderboard rules don't mention it).

Edit: Increased Dodge/Parry timing is now officially banned for Ultimate runs in the leaderboard rules.