Personally, I'd want to have direct communication with Celebrity Special Needs instead of going through a third party. Unlike the normal customer service side who will not talk to you if you have a TA, special needs will. That way you can be sure they are aware, and you can be sure that they understand what you need, instead of it going through someone else. Even if the TA has made contact, you can also talk to them.
Wheelchair Accessible Cruises | Celebrity Cruises (Contact is on this page)