CKO wrote:Can units with Dimensional Translocation use Prismatic Dimensional Breach stratagem? Are those units considered to be in strategic reserves?
I believe it's a "no" as p5freak says. "Strategic Reserves" is a very particular thing and using "Dimensional Translocation", or any form of "deep strike", does not put a unit into "Strategic Reserves".
However have a look at the C’tan Shard of the Deceiver, that can put units into "Strategic Reserves" at the start of the first Battle Round before the first player takes their turn (for free). That would then let you use the "Prismatic Dimensional Breach stratagem" on them.