1. Droid PositionVoss-Ka, at the top of the Tower of Prophecy.
2. Droid PositionThe Old Paths, Eastern part, look up toward the Voss-Ka building, droid is next to it (If you try to reach this point from Voss-Ka, you will not find droid there).
3. Droid PositionThe Pelath-Ri Marches, at Northern map edge point your view toward a gap.
4. Droid PositionThe Pelath-Ri Marches, Northeastern part, under the roof of upside down letter “U” building.
We would like to thank Oorin for sending us new screenshot.
5. Droid PositionThe Nightmare Lands, Northwest from The Dark Heart, at the edge of small hill.
6. Droid PositionThe Gormak Lands, Southwestern part, inside a small “watchtower” attached to a rock mountain.
Source: Official MCR-99 droid locations (hidden planetary achievements), MCR-99 Droid Locations post 2.0 on Swtor official Forums. We would like to thank SWTOR community members for all additional information.