Well you said that your dog doesn't have any aggression for wp? I am confused on what that means, i know you edited your post but I am a mod and can see all! lol
But you also were talking about health tests and and you said the vet said he had nothing wrong with him.
DO NOT BREED YOUR DOG. not to be rude or mean just trying to give you some help. You know very little about what type of dog you have by the questions you ask and I know everyone has to start somewhere but you have a ton to learn before you even consider breeding. You dog also is very obviously has been crossed with something and I would guess American bulldog. If you look at his up turned muzzle and the roundness of his head that says it right there.
Just because you have a dog who can make puppies does not mean you should and in this case I do not think you should since your dog is not standard or an APBT
or well bred bully. If you want to breed again you do have a lot to learn but also you want to start with the best stock possible.
As far as weight pull you can see if he has the drive for it and we have a whole section in this forum dedicated to weight pull. Check it out and get started! He does not have to be intact to do wright pull!