I don't know much about cherries, but if these are native black cherry (P.serotina) seedlings, I don't think that the sweet cherry varieties you've got will work on it.
If, however, it's a seedling of one of the sweet or tart pie cherry types, you might have some chance of success.

I would graft it at 3 feet or so. I've topworked a bunch of trees with the same considerations. If grafted at 6 feet the first fruit are at 8' or higher and it isn't easy to get into the tree.

If you could put a simple fence or barrier around it for a summer it will probably grow tall enough to get past browse line.

I budded some sweet cherry onto wild/volunteer cherries a the edge of my property last summer and was surprised to see them pushing this week. I had to chip bud them because the bark wasn't slipping for a T-bud.

you can see fruit buds on the smaller tree in the one photo. These are not wild black cherry. The fruit on the one was over a 1/2" in dia. last summer.

I guess I can only do one pic at a time. Here is the bigger one. It looks really tall from this angle but the second branch is five foot or so off the ground. I could cut first branch and trunk about three foot up and more area to graft. What do you think?

Here is the other tree. So should I transplant and graft or just graft and transplant latter? Also the buds are just starting to swell with no green showing. I am forecasted for lows in the lower twenties next week. I would like to transplant and graft soon. Maybe transplant now and wait for other trees to bud then graft. I'm not sure if the grafts will have a chance though if I put them on a tree that was just transplanted, but then because the top will be cut off maybe it will work. What do you think? Should I do it as a two year process, or go for it. Maybe try one in all this year and the other in two years?

It seems too large for a satisfactory transplant ....it could die on you, especially when you have to hand dig.
If you do, let it grow for one season and graft next year.

OR
See if there are any small suckers coming up,..these will be good, again, grow them first one season.

OR
Dig about 3 foot out, about 3 or 4 places down to the root ball and expose just a little roots,..they might sprout,...induced suckering..harvest the following year.

I guess if the trees die I don't have nothing to loose. They are just like brush to me now. My plan to transplant wasn't to take the whole tree. I was thinking on just taking a stump and some of the root ball. Then I was thinking maybe graft onto the stump this year with all its roots still in the ground to give more chance for the scion to take and then next year take the stump with water shoots and root stock to a sunny location. Do you think I should take the stump and what root ball I can get and give it a year? Scion wood isn't a problem I can harvest more next year too off my trees. I don't think I can get a big enough root ball to take the whole tree. I think it would die too. I was thinking little root ball would sprout the stump. When I cut the roots in the ground maybe the ones left will sprout shoots too.

If you graft now, the whole tree might still die next year in the transplant.
You can take some pieces of root ball home and most likely it will sprout. Since you're in the digging, let some of the roots a little exposed, might sprout also. I think it's worth saving the rootstock,..you might have something desirable.

Don't graft- transplant. Trees under stress are lousy candidates for grafting- even if they take they may runt out. I would graft after the tree has had a year to adjust and return to reasonable vigor.

Those native cherries are like weeds and if you can manage to get enough root you can probably successfully transplant up to a 3" caliber tree for sure. The problem is that it is growing in a tangle of roots from other trees- I don't see how the labor if worth the tree- but I don't do this for a hobby. If there are black knot galls on the trunk it's worthless. They are the typhoid Marys of that disease.

If it's native yes, but my understanding it is not?

Okay I dug it up and moved the whole smaller tree. I thought I would get dirt with the roots but it didn't work out so well. I got bare roots. I got a root sections about eighteen inches with a bunch of hairy little roots kind of like you would see if you scaled up a little root graft picture. I should have taken a picture sorry. I have some 1/2" dia roots cut. I put it in the arch of the sun as it goes threw my woods in the back of my vegtable garden. Itsnext to a maple tree but the sun will hit the fruit tree as it comes around. I mixed up some rooting fertilizer I got last year from the nursery. I mixed it with soil, rain water and some rotted sawdust. I mixed it in with rain water and my hand to get it into the air voids and filled the hole up like that till I got to the top. Then a blanket of rotted horse manure and leaves to shield the sun. This is what the top looks like in the one picture. Do you think I should top it to one small branch?

the bottom. It looks crowded because it's where I threw tomatoes cages from the garden to the back of the garden where I put the tree. The box is where I planted pumpkins last year. They took over the whole garden. not doing that again this year.

I'd let it be and see, graft next year or when it's established.

Ok, I had cut most of the lower branches off a couple years back. I didn't know at the time it was a fruit tree. I just wanted those branches out of the way of the mower where the boat gets parked against the woods. I cut a bunch of vines and shrubs at the time too just clearing out foliage. I should trim those back in a couple years if it takes. We will have to see. I'm running out of full sun areas. I have some left in my lawn, but I'm also trying to make it so I have a yard too! lol. This fruit tree thing is addictive. When I found these trees I just thought what a waste and wanted to move them.

Well so far it looks okay with leaves starting to form, but it has a long way to go. I didn't transplant the bigger one. It has lots of flowers on it now, and more leaves than this one.

Here's the tree I didn't transplant. Its hard to see with the background but the white blossoms are the flowers on the branches.