Lots of questions, so here we go:
As to the challenge at hand, is the engine retractable?
Not that I am aware of....I can't really see where it would retract to.
The dotted line shows the fuselage profile I think.
Correct LM. The bit above the dotted line (other than the engine) is the wing.
Would you call it a motor-glider or ultralight or both
Its classified as an ultralight.
Apparently it comes in two u/c settings, tripod or tailski.
It has both a nose wheel and a very small tail wheel.