Vulcan never died. This entire era is marked by characters acting in ways we thought they wouldnt. Like Scott and Jean sipping cocktails with Apocalypse, given their history. I dont believe there is any indication that Xavier is manipulating the memories of anyone. These characters all still know their history. There is a greater propose though that supersedes holding onto old grudges
I believe that Krakoa itself might have some form of psychic influence on everyone but thats not something I expect to see revealed anytime soon