That entire scene when he saw hell was mostly explained here. That demon Shinra saw and the guy with the claw marks on his face. I was wondering who that guy was
She's certainly not making things easier for him, but I think all the preacher did that time was predict when and where Sho would awake the adora link. Haumea and the other were just there to pick him up. The fire and their mom getting turned infernal would've still happened either way, and with things the way they were the mom probably would've been put to rest right there without Haumea using her to bring Sho out. She seems like one of the ones that kept more of themselves than normal, so this way around he might be able to see her again eventually without having to fight her or anything.