Speaking from experience (working class family, was the first person in my family to continue in education beyond 16, went to Cambridge, now have a PhD) everything you have suggested is great. But it is going to be very very difficult to replicate the life (and, perhaps, the confidence) of a far richer child. Yes, you can take them to the museum, but there is so much more to it than that.
I would work instead on building confidence, and building knowledge of the interesting parts of their own family history. When I first arrived at Cambridge, I was painfully aware of how much posher so many of my peers were than me. I felt less than them and ashamed - ashamed of my class background, of my family's poverty, of the fact that I hadn't ever been abroad, of my accent. And I had been taught this, in a way, by my parents who really deferred to authority and to those they saw as their "betters," and by my school who said that Oxbridge wasn't for "people like us" and discouraged me from applying.
I soon realized that I was as bright, and often brighter than my undergraduate peers (I went to very poor schools and taught myself, whereas some were really spoon-fed at exclusive private schools and weren't actually that bright after all). What took me a while was realizing that I was just as good as them, just as interesting, just as worthy of having a say. I wish my parents had taught me that our family history (a family history of overcoming remarkable adversity, of brave migration, of early trades union activism) was rich and fascinating, that I- as I was, with my thick northern accent - was just as good as anyone else, and that I had experiences and perspectives that were valuable.
Once I found that confidence in myself, no door has been closed to me. It's the confidence that matters, not trying to fill in gaps, or to put together a replica of a different life. If your child loves museums and books (and Mandarin, and opera, and skiing, whatever) great too, but that isn't the most important thing.