I haven't tried flax seed gel, no-- I'm rather lazy and only in a DIY mood on occasion And I think you're right about at least some of the frizz just being short hair. Most of it's around my crown and very, very curly; which would make sense, seeing as my hair curls up more the shorter it gets. (Still dang annoying, though. Hurry up, little guys!)

I think I might be on to something, though! I remembered to do the stretch test on my hair when it was wet-- and despite my thoughts that my hair must be too dry, my hair stretched, and stretched, and did not go back to its old length. So I pulled out the packet of Ion Reconstructor I had gotten when I first started suspecting protein... and paid for it with ridiculously fuzzy, undefined hair the next day. Clearly my hair hates protein, so needing more of it wasn't the problem, right?

...except then I remembered Ion Reconstructor had Cocamidopropyl Betaine in it. Which I know my hair hates. Good job, me!

A trip to the grocery store to get some AO GPB, followed by leaving it in my hair overnight and the stretchy problem is fixed and my hair seems much, much better. (The bits of hair that frame my face are curling!) Hopefully it continues to behave itself even after it dries Maybe this is what I was missing!
2b/c, low porosity

Low-Poo: Diluted L'oreal Eversleek shampoo
Co-wash: Currently Trader Joe's Nourish Spa (old formula)
Rinse-out: None! I just do gobs of leave in.
Leave-in: KMF Big Hair (HG! aaaand a discontinued formula. If anyone else knows a proteiny aloe and BMTS based conditioner I can try to replace this with after my stash runs out, let me know!)
Styling: FOTE AVG (HG!), Lush's The Big Tease gel (RIP...)