No, it won't affect development or personality. There will still be plenty of hormones for him to develop normally.
I've heard of them dropping as late as 6 months, but generally if it's not down by 10-12 weeks it's not coming down. At only 7 weeks, it still might.
Yes!
With retained testicles, it's the retained one that is at higher risk for cancer. It *might* be ok until 2-3 years old, it might not.
If it were me, I would do surgery to remove the retained one pretty soon, but leave the other. Then finish the neuter at 2-3 after he's fully mature. That removes the cancer risk as soon as possible, while also ensuring he's able to develop normally otherwise (plenty of hormones will be produced by the regular testicle).
Problem with this is that removing a retained testicle is much more invasive, and thus more expensive, than a regular neuter. And of course, doing 2 surgerys is going to be even more expensive. Many breeders will discount a cryptorchid pup, or contribute money toward the neuter, because of this. So might be worth asking your breeder about.
Correct. Cryptorchids/monorchids and neutered dogs are not allowed in conformation shows.
