So I've had some that taste fruity or like unsweetened chocolate.  Some are very good.  At the wrong time or a bad tree can be bad though.

Just grow it up and graft it to something good if you don't like the fruit.

I got three yesterday.  They were good, but not as good as in former years so far.  The "tree ripened" mexican Kents I got were actually better based on the first one I ate.

I've dug up a loquat and moved it if that's what you mean. When transplanting small loquats I actually keep them in water until new white root nubs form.  For big ones 4 feet plus I cut back the top (be careful of sun burns) and kept the soil wet for a while at first.  They seem to survive, but I don't do it in summer here (low humidity/dry soil).

I think Vietnamese is Na Dai aka the chewy one in California at least.  Vietnamese Cherimoya is just a tree that was growing in California and as far as I can tell has nothing to do with Vietnam.

In addition to those listed Honeyhart is a good variety.  I showed up to a SD CRFG chapter grafting thing and they had a good selection of wood.  So might want to ask them what grows/tastes best in the area.

I had something at Ong's that was African Pride 2 (seedling of?) which was pretty good.  Not as good as top tier Cherimoyas, but better then low tier Cherimoyas.  It was chewy though which allowed you to eat slices in a car while driving.

Something else is the best ones arn't always the best ones every year in a taste test.  I've seen this in my own tests when trying different varieties as well as people who go to the Irvine thing.

I'd just got a tree then graft on things you find out you like honestly.

 

 

If it's from seed it still might not be mature even after 7 years.  It may also not be a lemon depending on source since citrus hybridize.  Just graft on a scion of a lemon if that's what you want right now. 

That's the type I have I got from Bonita.  Red flowers, but green foliage/new growth.  Don't suppose you know variety it was suppose to be?

I've never been because I've always been pressed for time, but there's a rare fruit planting at the Thousand Oaks botanical garden.  No idea what's in it.  Fairly close to the 101.

For loquat just do the CRFG scion exchanges in winter.

A lot of people tell me that Sebelle isn't a great White Sapote.  Maybe go for Vernon, Walton, Rainbow, Malibu 3, or something else.

You can probably have one cheap if you plant a seed and just graft in a year. 

Genipa americana?

Burnt Ridge in OR. use to have them.  Heat is what gets them. 

Even if you find an ultra mild SoCal location and have it next to a structure there's still a humidity issue.  I'd try pushing some of the more realistic tropicals for the area.