How can I get my defrosted pizza dough to transfer from peel to oven?
Keeping a pizza from sticking is a process; the spot that sticks on the peel probably developed before it was on the peel.  Use plenty of flour on the counter while forming the crust. Make sure to move the crust around frequently, and work fast when assembling the pizza. While stretching the dough and between pizzas, occasionally feel the counter. If flour is sticking to it, scrub it away with your fingers and sprinkle on more flour.
Once the pizza is on the peel, shake it frequently to test it and to keep redistributing the dry flour underneath it. If you see a spot sticking and shaking doesn’t dislodge it, don’t be shy about lifting it up and sprinkling flour underneath: if it sticks a little bit when you shake it, it will stick, and more severely, when you transfer the pizza.