I like the concept of that Vader droid, it's hard to do things using parts from Darth Vader figures, but something like that really works well.
The Mandalorian is a very cool design. I like the use of tusks on his helmet, it's cool to see a modified Mandalorian helmet that still has the Mandalorian-vibe to it. What are you going to do to his legs? I think if you just repainted the thighs they might look fine, maybe you could fill in the gaps with some putty or something.