What we're seeing in the first photos of this mystery plant is the "new" growth of whatever "it" is.
It would be better if we could see photos of the foliage as it matures.
Look at the photo in my link below and you'll see the mature stems from last years growth.

The thread "What is name of this plant?" in Plant ID forum

I may very well be all wet here, but this looks like Lophostemon confertus to me...formerly known as Tristania conferta...or some variation thereof.
The new spring growth on these trees look like the ones in the OP's first photos. The foliage, as it matures, flattens out and becomes more pointed and the color changes to a darker green. We have these as street trees around here and they look like this right now.
The older bark on the stems also ,leads me to believe this may be Lophostemon.
See what ya'll think. Our plant database photos here don't show the new growth.
Again, I may be way off base.

Sorry...the link I posted isn't correct.
Look at the LAST photo in the original opening post of this thread.

Lophostemon confertus leaf venation is different, plus it has an Eucalyptus type seed capsule.

https://en.wikipedia.org/wiki/...

Any thoughts on where to look Janet. I'm stumped. 🌎

Maybe Trade Winds Fruit? I bought a lot of citrus seed from there some years ago, I had quite a few plants in a greenhouse but they eventually got frozen.

http://www.tradewindsfruit.com...

Annona glabra is similar ..

http://florida.plantatlas.usf....

A closer look at the fruits, the do look to come off a long stem which appears to have been a long flowering stem.

As Leslieray suggested, can we see a picture of the fruit cut in half, maybe one cross-wise and one length-wise. If there are any seeds large enough to see that would help too. I keep thinking Ficus of some kind but again I don't think the leaf venation fits.

I might be getting somewhere! Check out Prunus lyonii ..

http://www.calflora.net/losang...

https://www.google.co.uk/searc...

I think this is it! Native to California Catalina Islands

https://selectree.calpoly.edu/...

I think you nailed it, Janet! I knew it looked familiar, but just couldn't place it. The leaves look very light for that species, but that could be the sunlight or the camera.

And here it is in our database.

Catalina Cherry (Prunus lyonii)

One photo on the second link shows lighter leaves Carol. I wonder if the tree has had a burst of new growth, in the last pic you can see a flatter and perhaps darker leaf in the background.

It was Leslieray who boosted me into thought, from the trade wind fruits site I googled one with no photo, that brought me to the "What's Blooming at the Los Angeles County Arboretum" link but in May. I skipped back to March then April and that's where I found it!

These photos will make a good addition to the database zuzu.

I think they'd enhance the database entry too, Janet. Let's see what akumarer says.

Well, I actually lived with one in a rental property, but that was 48 years ago, so memory is a little vague.

I was just checking for toxicity. Now I'm not so sure...again the leaf. Got mixed messages on toxicity and leaves. Most sites list it as small tree of shrub. The CalPoly link says 25-35 ft tree.

http://www.calflora.org/cgi-bi...

According to this article it is the seeds that are toxic, the fruits have been eaten:

http://www.wildflower.org/plan...

I saw one site that said edible. There seems to be some controversy on this tree.

It's possible for the flesh of fruits to be edible but not the seeds within, I think that's what they mean.

That's true. There isn't much flesh on a Catalina cherry.

Way to go. I did read some info about how difficult it is to find P. lyonii because it so easily hybridizes with P. ilicifolia which is growing here in the Native Plants Demonstration Garden.