Growing pawpaw from ... another pawpaw?

I saw a thread discussing pawpaw from seed, my situation is a bit different.

Ten years ago, I purchased two native pawpaw trees (from Edible Landscaping, Afton VA).  One tree looks just fine, the other ... is now about 20 trees.  The original is in the middle, maybe 15 feet tall, and it's surrounded by 20 or so treelets, mostly 4-6 feet tall.  

1.  Why did only one tree have all kinds of babies?  My friends say 'That one must be a female then', though no one knows for sure.

2.  Can I dig them up and re-plant?  They're way too crowded to stay there long-term.

EDIT to include:

3.  I just thought of this:  Did the one tree bear fruit, drop them, and these resulting babies are from the dropped seeds?  Pawpaw seeds have a reputation for being real finicky about germinating, am I having tremendous luck?  I haven't gotten fruit from the other tree yet, maybe I just answered my own question.

many pawpaws sucker a lot from the roots. and some don’t as much. unless you think there was a lot of fruit that got missed over the years (or, with all the little ones the same size, a lot all in one year), that’s what i think is happening. if you can get enough root they can definitely be separated off and replanted elsewhere. if they’re suckers, the root may mostly go directly to the older tree.

Reasons why you will have a "thicket of pawpaw"
1) Pawpaw send up "root suckers" aka clones. They send up more suckers when you prune/damage the existing tree.
2) Pawpaw fruits that fall to to the ground will germinate and turn into trees.
3) Humans and critters that eat pawpaw fruits and then throw/spit/compost/etc the seeds on the ground will

FYI:pawpaw trees normally need two different cultivars nearby for it to bear fruits.

Pawpaws have male and female flowers and can self pollinate. However, they don't because the male and female parts develop at different times. I'm guessing the one with fruit flowers slightly later because the female flowers bloom first. The one that flowers earlier is producing male flowers at the same time. When it was producing female flowers, there weren't any male flowers locally.

Pawpaws have deep taproots - you really don't want to break them. Micheal Judd, author of "For the love of Pawpaws" grows pawpaws from seed in very tall thin pots for this reason. And to avoid spiralling. He suggests at least 12 inches deep. He also suggests planting seeds in the autumn, so if you have any seeds from the tree with the seedlings, then use them.

Anecdotally, my pawpaw tree is the only one of its kind in the vicinity. The nearest that I'm aware of is about 3 km away in another valley separated by quite a lot of hills and trees, so I doubt if any pollinators are making that trip.  I doubt there are any wild pawpaws in the area yet, considering they are not native to Japan.

It fruits, though minimally, all by itself.

I have three pawpaw trees, only one flowered this year because the others are still young.  The one that flowered is setting fruit.  How can this be?