Pics of Tree 2 here:

Pic of Tree 3 here.

Tree 1 probably is not a lemon or lime due to it's larger petioles. Tree 2 looks like a lemon or lime and the leaf scent as Denise mentioned should allow you determine that. Can you get a closer look at the leaves on tree #3?

The first picture shows a hole at the bottom of the fruit so maybe a navel. Tree 2 may be a a lemon as the end is pointy. A close up of the whole fruit would help. Tree 3 I cannot tell because of the distance. Crush the leaves or cut a stem and you can tell by the scent.

I agree with Denise about Tree # 1 definitely looks like the Navel Orange. #2 looks like a lemon tree possibly Lisbon,Eureka or Meye. #3 is anyonea guess unless there is a close up. Good luck with the search, I am sure when the fruit ripens and you can taste it you will have a more solid idea.

Thank you so much Denise, Fruity Paws, and Julian! I will look up how to know if the fruits are ripe and also test out the smell on the leaves. One question about the lemon (Tree 2) specifically: some of the fruits are turning brown, but they're otherwise still green. Certainly none are yellow. Do I wait until they are yellow to pick? My husband and I are trying to remember, but we don't think they ever turned yellow last year. I'm not in any rush to have the fruit, just don't want them all to go to waste.

I got some better pictures of Tree 3 this morning. Do these help? The leaves and fruit are significantly smaller than on the other two trees. Each leaf is as long as my finger, at max, and has sort of a segmented shape.

A picture of the brown fruits would be helpful as it could be some sort of fungal problem. The leaves from tree 3 do not look like oranges, lemon or mandarin. I have lots of those and none of the leaves on them look like yours. I am guessing grapefruit.

Tree no 3 is HUGE

Haha I know, it is huge! I don't think they're grapefruit, because the fruits and leaves are much smaller than a grapefruit tree we also have. Unless there are other varieties of grapefruit?

Here is one example of a brown fruit. What do you think?

Because the leaves are discolored as well, when was the last time it was fertilized?

they look like a sudachi actually to me

Possibly due to poor airflow with high humidity-wet conditions? I notice that palm in pic 3 and take it you are in central or north Florida?

Tree 3 might be a rootstock that has overgrown the scion due to a long period of neglect.

You'll have to wait to taste the fruits.

Tree 1 is probably a Navel orange.

Denise, no time recently. We just hired a landscaper bc our yard is too much to handle. Socal, thanks for info on Trees 3 and 1. Matt, we're in south Louisiana. Definitely lots of humidity and wetness. Bklyn, you might be right about the sudachi!!! I'd never heard of that, but the previous owner of our place was Japanese and the fruit resembles what's on google. Thanks so much for that!

If they are sudachi, they are picked green