Our TA with Dreams is also Cathy... and Donna is also supposed to be great. My first contact did just happen to be Cathy, but from what I have heard, if you are cruise-only, then your booking will probably be assigned to one of them at that point? I know that Cathy is a Dreams -
DCL cruise specialist. I would go ahead and email Liz, and ask her about this, and ask if somebody else will be your TA, she will let you know. Or maybe just mention that you did hear of DU and your desired TA thru a personal referral. Probably not to big of a deal.
I have not emailed a whole lot, but when I have, I have ALWAYS recieved a prompt response to any question! Cathy got us a particular Secret Porthole Room we wanted, by putting us on waitlist, and she changed our dinner request to late seating, requesting a 4top for our family alone, if possible. They really know how to handle these ressies with DCL.
Don't forget to ask about first-time-cruiser shipboard credit (code REF), and any other credits that you may be able to get!