Well in my opinion, there is a huge difference in the pattern between Snowlark and Dots and Dashs. Anyway, you may also have noticed that the photo options listed in the Minnesota hybrids list is not synced with the Minnesota hybrid photos. There are some pics there that are not displayed in grey on the list. A few other "improvements" that still need to be done - as I said the site is pretty newly revamped.
There is no distinction that disallows certain divisions on the MN hybrids list, as far as I know. If they are missing some (and I'm sure there are still many), it's only because they don't know or haven't gotten to it yet. Our present president of our Society has the giant book of all registered lilies, but the listing doesn't differentiate anymore as to who actually hybridized and who actually registered. At any rate, if you have any names, I'll surely pass them along.