Mesembrine alkaloids still seem ideal for your purpose, legally unrestricted and abundant in your native plants. They lack the visionary and introspective qualities of tryptamine or phenethylamine hallucinogens, but they're very respectable, extensively studied for safety and efficacy in animal models.
You could try crystallizing some new salts with friendlier solvent systems and counter-ions; the literature reports mesembrine hydrochloride from ether and not much else (though I did see some patents). You could characterize their physical properties as potential active pharmaceutical ingredients, or study purification by crystallization of the crude plant extract. Improved purification is actually useful, since total synthesis doesn't seem economic. You could also try improved chromatographic purification. Patnala reports a method with many different solvents and incomplete separation, and perhaps e.g. a well-designed binary gradient would be simpler and better.
Or you could analyze some plants, collecting many samples from nature to understand the variability. Sceletium tortuosum has been studied enough that it's reasonably well-covered already, but not Delosperma echinatum, Aptenia cordifolia, etc. (since the literature says they're positive but my plants weren't). There are published LC and GC methods, though if you wanted to do some method development then it would be interesting to try LC under acidic conditions on a phenyl-hexyl column (or other column with pi-pi interactions). This would be greener than Patnala's or my LC method since the eluent would probably be almost pure water, and I guess possibly separate better somehow.
.
