Also a follow-up. I received the MDP/DP cables from CA as above. They appear to be nicely made, and of good quality. I am using them to attach 2x NEC PA271W monitors.
I also have no start issues. However, with "computer sleep," I also occasionally need to off/on one of the displays to re-awaken it, and once or twice I have had to unplug and replug the cable to get one of the monitors to come back online.
This does not seem to be an issue with "display sleep" as much as with "computer sleep."