Every cactus is different in alkaoidal profile, you don't just have mesc and its close cousins as well. IIRC, theres quinolones, and others been detected, along with phens like hordenine, and many others. Regardless of whether were talking aboot lophs, or the various active trichro's.
And while mesc may be heat stable in solution, usually acidic, who knows what happens to all the rest. Longer/shorter cooks, higher lower ph water, different polar solvent extraction methods, so many factors.
You'd have to have a education, a decent analytical lab, and the patience to do some studies to get any relatively probalistic generalizations about alk profiles and how prep method comes into play.
I will say, making a resin with iso, evapping and dissolving in hcl water, filtering and reducing, then basing with koh, limo pull/hcl water salt gives a hydroscopic alkaoid that is active. Its soluble in dry acetone, and won't crystalize unless you have the tools to make it do so under annhydrous conditions, as the hcl.
Cactus extractions are like pokemon, gotta try em all. Even when you find one that works really good, they're all unique and have their advantages/disadvantages in regards to preserving the natural alkaloidal profile of the specimen.
Just good fun in my expirence :d, though time consuming. But thats part of the cactus game, and makes it special in its own way.