Yes. It is possible that a gandhabba may not have one or more pasada rupa (usually one) missing.
– Yes. One could be born blind and deaf. But that is very rare.
So, if the cakkhu pasada rupa is missing, that would be the case of a person born blind (jati andha).
– However, some are born without the ability to see, even if the cakkhu pasada rupa is there. If there is something wrong with the optical nerve or the visual cortex, that would of course lead to blindness. But, if those brain circuits can be repaired in some way, they would be able to see again.
– If the cakkhu pasada is missing, then nothing can bring sight to that person.