Hey man, welcome to the community (although most of it is really at gatherings). Glad to hear you've gotten interested in tricking its tough at times and at first maybe a little slow but give your body time to adjust to this new stress. Keep doing what moves you've landed, whether it be tornado, pop 3's, backflips, handsprings. They are all pre requisites to higher level moves which are really just the basic moves with variations in twisting and body position. But they all stem from a few moves.
The flexibility will come though! No need to force your body too much =] ! I wouldnt suggest stretching a whole lot as tricking makes your muscles do this already. If you cant land a move a particular day but you could land it, listen to your body, try another trick that you can land consistently and work on slightly adjusting that move, moving shoulders, leading with one leg, or power through the move... make it fast, do the move slow, make it floaty. Doing so will allow you to get familiar with the possibilities of how your body will move in the air and throughout the particular trick. It will also works it way into other tricks!
Get a really good warmup before you start throwing moves around, if you have one solid move that you can always land no matter what, do that a few times, get really warm, almost at a brisk sweat before you start to trick. After that you could do a little stretching and get your muscles acclimated to lengthening and contracting, or do some extended bounds for a few minutes, walk on your toes and heels and warmup your calves, ankles and shins. Make up drills for this, make it fun! I usually take a step onto my heel then quickly pop up to my toes like im going to jump and then come down slowly and continue with my other leg.
Dont forget to warmup your upper body too! Its so important as well as your core. Do a few standing twists back and forth to the sides using your obliques. You seem like your in good shape. Always think light on your feet! Best of luck in your training, it'll be almost 2 years for me this coming drednt gathering.. pumped!