Revit prefers native Revit objects. It's best practice to avoid importing from AutoCAD if at all possible. If it's something like an MEP RCP, use link CAD (and consider Current View Only as well) instead of import CAD. If it's a family, you can temporarily import it to Revit to use as reference, but purge it out before loading your family into the project.
Just remodel the dwg object in Revit.
What I heard people do is convert dwg to sat and then import into Revit.
Why not if you really need it? Such as some details already created in DWG.
I wouldn't, I know a few things/objects aren't available in Revit but just don't bother.
No, just no.