I was hoping that Sony Japan would get going with these quicker than just doing them as 50th anniversary editions but given the elapsed time here, that doesn't seem to be the case. They were a bit late with reissuing the first album, but the SACD of Abraxas was 50 years to the month of the original LP release.
If that holds for the remaining titles, you can expect Santana III in September of this year, and then Carlos Santana and Buddy Miles! Live! in June of 2022 followed by Caravanserai in October of that year.
It's also possible that the release schedule has simply just been slowed by COVID, as all the quad tapes for these albums are held in the US in vaults controlled by Iron Mountain that have all but been shut down by social distancing regulations for the last year.