-Zero knowledge from previous books is required. Maybe you'll be unfamiliar with Xorn, Monet, Krakoa and some others but that doesn't matter. Hickman explains everything you need to know.
-This event only takes place in HoX and PoX (12 issues total), nothing else is required. Hickman tells you the reading order on the last page.
-No, there are two waves of X-Books following this starting in October. Only Hickmans New Mutants interest me but feel free to check them out. FYI Psylocke reverted back to Kwannon and Betsy is now Captain Britain.