SS3 Goku ought to be stronger than Ultimate Gohan, though that's basically all we can say. I guess you could use him being so confident in facing Beerus that he even thought about powering down to SS3 as evidence of him having possibly surpassed SSJ Vegetto when Kaio had already placed Beerus in his own league, though I'd chalk that up to a mix of modern Galu idiocy and him probably not being aware if Kaio sensed their fusion in either continuity. Personally, I'd place him somewhere between Ultimate Gohan and Gotenks Boo.
As for Vegeta, he was able to make Beerus bleed when Goku confirmed fusion wouldn't work against Beerus, and there was no indication that Goku knew Beerus had far more power when he admitted SSG's power was a world he never knew existed. That said, Enraged SS2 Vegeta > BoG SS3 Vegetto.