On the elbow question, I've had some success in the past with sawing the arm in two at the elbow joint (at a slight angle / \ to allow for movement) then hot-gluing some bendy foam cables (don't know their official title) in each section of the arm, allowing for elbow movement. A bunch of them together are more than strong enough to hold any pose you like. It worked well for me at least.
If you can't source the bendy foam things, I suppose you could use some foam pipe insulation with doubled-up wire inside (coathanger wire perhaps?), it would do the same job.