I moved a volunteer Kousa into a better location last year. It has done just fine. I read in a post somewhere that a homegrown seedling may take longer than bloom than a nursery purchase. I'll let you know when mine blooms.

From what I can figure out, dogwoods are outcrossing like apples, meaning their flowers can't self-pollinate and thus all are natural hybrids. Fancy named cultivars that you buy are all grafted (just like apples).

Because they are outcrossing, their genetic information gets well-mixed every time seeds are produced. So the seedlings will not be like the parents, but will probably vary widely. In my opinion, that makes them worth keeping. They'll all be attractive, and all unique.

I think you should bring them to the fall swap :-)