At this point, I know that no matter what I say, you’ll have to “correct” me. So I will make this my last reply.All sata III drives must follow the sata standard. I have yet to come across a sata III ssd that didn't work with a sata I or II controller. I am curious if anyone has run into this situation. I have only used sata III ssd and mechanical drives with old machines, Mac and PC, with no problem.
Sata I and II ssd drives have not been made for years. Finding a new one will be difficult and/or expensive.
https://kb.sandisk.com/app/answers/detail/a_id/8142/~/difference-between-sata-i,-sata-ii-and-sata-iii
The older aura ssd may not work with high Sierra and apfs (https://forums.macrumors.com/threads/apfs-not-compatible-with-owc-ssds.2072100/) while the 13" 2010 MBP runs high Sierra. I had it installed on a 13" 2010 MBP with a Samsung 850 EVO sata III drive, apfs, and no problems at all.
There is no set standard that all SATA III SSDs have to be backward compatible. As you said yourself, SATA I & II are standards that haven’t been used for years.
Those Aura SSDs only have issue with High Sierra with certain Mac models, has nothing to do with the subject of SATA I/II/III, and, since OWC is working with Apple on a fix, might be fixed with the next High Sierra update, as that issue may have to do with the Mac or the OS not the SSD. APFS is also not compatible with Fusion drives yet, but, will be in a future High Sierra update. https://blog.macsales.com/42466-a-note-on-high-sierra-compatibility-with-third-party-ssds
I would also like to note, that, while 2011 MBPs have SATA III capability, some 2011 & 2012 MBP models, if you upgrade the optical bay with an HDD or SSD (using an OWC data doubler, or ifixit’s dual drive), you must put a SATA II drive there. The (first for Apple laptops) SATA III interface in the optical bay was unreliable and would work intermittently, or not at all with SATA III drives, but was fine if the drive maxed out at SATA II.
If you really want to argue more, please start a new thread on that subject.