I can't find the thread that we originally talked about Xavier just mindwiping the Original Five once they made it back. It didn't occur to me until I reread All New X-Men 5 recently. If they did go back and if Xavier did mindwipe them. Wouldn't he still have that knowledge and memories of their adventures in the present? Wouldn't he, himself, make a bigger point of guiding Scott so that Scott doesn't end up killing him in the future?
During Rise and Fall of the Shi'ar, he may have just stayed in space with Havok/Polaris/Rachel so that he wasn't on Earth, annoying Scott with his inability to do anything of worth. Or he would have told Cyclops to not go to the moon and have Tony Stark split the Phoenix Force into five segments. Or he would have told Scott to go to the moon, then Scott wouldn't have gone to the moon and problems are solved.
Or Xavier would have just not volunteered to talk to Cyclops when he is going full Dark Phoenix and just stayed home and let Scott run his course.
If the Original Five go back, Xavier will fix the problem. Now he just has to wait until one of them learns he marries Mystique and either avoid that or speed that connection up.