Sorry I haven't got back to you before. The easiest way I can think of is to look at those names in the IGI for each of the countries. I fairly sure most of those names will be found in Britain before 1800 but none of them are obviously Welsh.
Hope you find some answers on this site. It's been a long time since last we chatted. I'm related to Sarah Ooley Tiffee McIntosh. I don't think I have much or anything new on the family, I've been working on my main branches. But I'm always interested in the outer "branches".
I know a man here in Denver with the last name of Mays. He believes himself to be part native American, so spells it sometimes Maize(like corn). E-mail me personally at:email@example.com, since this person is living, and I'm not sure of where he want's his information to go.