This trade seems obvious, no? San Antonio does not need a 31 year old veteran who is only playing 15-20 minutes a game currently. They may be holding out for a first round pick, but the package below clears them of any salary obligations for next year (Cedi is non-guaranteed) and gives them a young project player in Windler. Throw in a second round pick to SAS as a sweetener and I think that's a pretty reasonable trade for both teams. This trade also keeps the Cavs below the luxury tax line this year.
You could also substitute Okoro for Cedi. SAS won't get salary relief as Okoro has another year, but he would also be another young developmental player. I would prefer to make the trade with Cedi.
McDermott is 6'6, is shooting 41% from 3 this year, which is exactly his career average as well. He is a sieve defensively, but I think the legit shooting threat he brings can nullify that to an extent, especially if he is playing with Mobley and Allen.