I do have what I think is the final question and also a suggestion for anyone who is reading this post.
Both my wife and I will be traveling in London. Do we have to get one Oyster card for each of us or can we share a card? The reason I ask is that when we buy a prepaid card for travel in the New York subways, we share a card. I am not sure if it is the same in London.
Now for my suggestion to anyone who is reading this exchange. I was planning to buy the 3 Three Palace Pass from the VisitBritain shop in the US for $56 each which would have saved me some money. Turns out that I can join the Historic Royal Palaces group (www.hrp.org.uk for 56 pounds for 2 people which is cheaper than the US cost. I get 5 palaces instead of 3, a 10% discount at shops and restaurants, a book, a subscription to a magazine, and some more goodies. This is a much better deal.
Again, thanks for the help.