3B1 expresses doubt more than the event, in fact expects it not to happen. 3B2 expresses uncertainty, it might or won't come about. 3B3 expects that it will happen. I seldom see any with the four versions mentioned in the initial post. All four of such variations are acceptable. 1 https://highkeysocial.com/story5844700/details-fiction-and-best-aquarium-shops-dubai