[AMOROSO!]

What if a person has pedophilic obsessions and wishes to alter it through therapy? Would it be permitted?

Well, you can ask your therapist for everything. Now, whether that can be done or not... I have no idea.

I don't think its possible to change your sexual beliefs though or it would be a widespread practice as many people are ashamed of them... what is possible is to supress them.

Would certain sexual deviations be preferred over others?

What do you mean?