I think DH enjoys work, he has a very active mind, so whether he will fully retire is unlikely. He will wind down by 60 I'd imagine.
The kids have a strong work ethic and do well in exams. They know they are expected to find work after uni, of course having a decent inheritance coming your way is helpful but they aren't getting that until we are dead - I'm hoping that's a long way off yet 😅
Both sides of the family are working class. We do help them out a lot but they never ask.
The only wealthy people we mix with are out neighbours. I find them a bit alien in some ways as many of them were born into wealth so they have no idea about the real world.
Your last question is the best one I've had. This is a concern. As parents we can't insist on making a future DIL sign a prenup, it's not our relationship to navigate, but I do worry about gold diggers. On the other hand I wouldn't want them getting girls pregnant without being married. The boys are aware it's not a good idea to make it obvious they have wealth when getting to know someone, they certainly downplayed it at school as their friends were a bit shocked when they came over for the first time.