Well... lol you have John's I have Williams. A zillion Williams - I pretty much think I have a William at least one in everyone of my lines. :)
As for why the Isted/Istead thing is that sometimes in the censuses the cenus takers just wrote down how they thought it was spelled... remember some people didn't know how to read or write - I assume they didn't know how to spell from that :) so they relied on others to help them.
And you didn't say where you were for all your Isteds.? just wondering :)