In addition I'm seeing loquat and what looks to be Clerodendrum also. At least some of these last are probably root suckers and should have odoriferous foliage if they are that kind.

The second pic you posted looks like cottonwood.....

I saw that too in the sixth pic. It's the only plant in the picture that show leaf veins that are close together like the pear pic. The serrations are much more pronounced so it may not be the same.

Not pear..... maybe morus alba. The only one worth keeping is the ulmus pumila that tom pointed out.

Is this the loquat or what?

I think that is the ulmus

Doesn't look like ulmus to me. But loquat shouldn't have serrated leaf margins like that, should it? I would almost guess oak.

Yes, the 6th pic is likely a Loquat, as there are several adult specimens around there...

Perhaps the others are all Clerodendrum, then?

Hug, I'm calling that Ulmus-probably pumila, but I could be wrong.

I agree with Embo, mostly what I see looks like clerodendrum, the big fuzzy looking ones, and loquat, the dark green serrated ones.

Loquat has serrated leaves as a seedling.

I don't see anything that looks like pear seedlings, but I've been wrong before LOL.