I question people that call themselves Spidey folk and have NOT seen the academy award winning Spiderverse yet.
1) The first Secret Wars arc is the best way to intro the new properties other than Avengers vs. X-men. Secret Wars would not need a 10 year set up to pull off like AvX would. First they fight each other, then they team up and fight the Beyonder. About the only Monkey Wrench in that story would be whether to include Galactus or not.
2) Scarlett Witch has shown glimpses of reality altering power when she mind fucked the others in AoU, but they mostly keep her telekinetic based. They had to keep her dumbed down, because she could have easily set off a House of M style event after Thanos killed Vision. “No more Thanos” Hell, she could have done it right after QS was killed in AoU.
3) House of M would be harder to set up. SW and QS were created with an Infinity Stone. Mutants don’t exist in the MCU, so there was no Magneto to give them the necessary genetic material to become supers.