Hello, unless your cut were very deep, 12 hours would be enough to close the wound, only fresh deep and actively bleeding cuts would pose some risk.
Oral sex is not considered a risky activity, because there are no reports of people getting HIV by doing it.
Regarding condoms, it seems you're having sex with several partners during the same session, it would be advisable to change condoms for every partner, every time you ejaculate, whenever a condom slips, and whenever a condom start feeling weird, like dry or if it gets cloudy, you sound check them regularly. For a session that long, you would need several condoms.
Hope this helps.