Hey Max , those trees look great especially the Lychee in ground. Whatever you are doing , keep it up. Very healthy leaves.
A few points
I noticed the potted stuff (lychees especially) seem to have salt burn or developing it. What kind of water do you have?
To keep them healthy try and purchase a chlrorine /hard water remover that you can attach to your hose
Why haven't you planted more in ground? You seem to have great climate . Space issues?
Other than that i think you are doing a great job everything looks great
I bet the lychee issue has to do with the quality of water you are using.
Maybe different rootstock are more sensitive to bad water than others/ accumulation of salts in a pot?