For most of your illustrations, the logic appears correct. I particularly liked the drawing with the two triangles. That's a nice illustration.
I think you'll find however, that if you attempt this while moving, your own motion will skew the plotted ships course. You'd be plotting the DRM (direction of relative motion) rather than the TC (true course). You may indeed even be able to triangulate on a location, but you won't have the correct track unless you do the vector addition and adjust for your OwnShips movement.
Most of your illustrations are related to stationary observations and those are all correct.... but the one where OwnShip is moving and speeding up and slowing down for instance, will only give you a DRM line (I think
). ...and it may even be OK if you just happen to be on a perfect parrallel path (as you chose to draw it).
I even think that example where you're showing OwnShip stearing an irregular course might only yield a DRM. The irregular course has an underlying motion vector that (I think) would need to be added to the plotted DRM. I could be wrong on this one... not 100% sure. Anyone can feel free to call me a doofus on this one, I haven't tested it.
(yeah I tend to appear when my name gets mentioned)