I think white spirit can leave a residue so maybe not ideal. you can get proper panel prep that’s not expensive but I just use something that can flash quickly like brake cleaner on rag I wouldn’t use wet wipes as the can also sometime have soap or oil in them . If a car has had a mix of paints in the past body shops use an isolator layer to stop it reacting .
I’d also use plastic primer on the bumpers most of the flakey bumpers you see is because they got painted in regular primer, which cracks when the bumpers move .