2&3. Randomly without capturing that elbow and being careful with the rotational forces that you are generating it is possible that you can damage your elbow joint. Not my words grandmasters words and quite a few physical therapy people.... Please please please please please start working these stretches very carefully with elbow isolation so that you do not damage the elbow joint.
Twirling absolutely not do that against me I'm going to just knock that stick out of your hand cuz you have no control over it. It takes some very specific drills to get the nice flat rotation that you see the grandmasters do. Very rarely do we open up our hand however it is only for a very specific reasons like the wing block of Angel Cabales Serrada Escrima.
And FMA is not karate yes they do have rice flails. However FMA does not have put things behind your back techniques.
And I've never seen Grand Master Dan teach any of this. Not only is i a Bruce Lee fan but also a big Dan fan.
Dan Trained with the original Stockton Grand Masters including Angel cabelas as well as Leo giron Max Sacramento and Tony Samara. As well as quite a few others including Leo Gaje of PTK.