TheSliver

Considering that neither Roshi nor Bulma were able to ride the nimbus, Goku would unlikely be able to, either, so it doesn't really matter whether Roshi would've offered it or not.

Yes

If the culling directive was absolute, then wishing the universes back wouldn't have mattered, as the Grand Priest would've simply had Zeno erase them afterwards. I guess it's a thing that they're supposed to do, but don't care about it that much.

Yes but he can't really know which events are true. The movies can be true, or it follows Super, or GT, or neither and the events are different altogether.