Sorry. Between all the goddamn DDoS'ing and Bad Gateways, it's been a real PITA to access the site. Things seem to be behaving now, though.
After asking around, it looks like the "HBA"s are actual JBoD HBAs and not cards that need to be flashed to IT mode. This surprised the hell outta me, as every time LSI cards are discussed, no matter the type, IT firmware has always been broached. I just thought it was de rigueur with these cards, hence my insistence.
Regarding the Ali Express SATA cards, I've heard that they (and similar) cards don't have much QC and ports can spontaneously fail, which is why I wanted to stick with a "known brand". I do admit, though, that they look interesting and will be bookmarking them for future consideration.
Flaming Dumpster, they're just standard SATA drives, most of them shucked, so they're white label WDs. I've accumulated 10 14+ TB ones and might get another if the price is right, especially when I fully get into the 4K HDR game. I mostly just want things to be simple, which is why I'm running Drivepool and not some fancy RAID setup.
My biggest problem is my indecision as to what to ultimately do. Having everything in one box would be nice, but would require a ridiculously large case and the final system weight would be ludicrous. Scaling the need back to a simple ATX case would probably save at least $150-$200 AND I wouldn't have to bother with the LSI card.
So, where would all the drives go? Into this, or something like it:
https://sabrent.com/products/ds-uctb
I could then build the actual system in something like this to put on my AV shelf:
https://www.silverstonetek.com/en/product/info/computer-chassis/GD11/
Like I wrote, I'm still vacillating between the two solutions, so nothing yet is set in stone. I am liking the Sabrent + Silverstone combo, though.