I've got a reply for Dnata,transfer is possible between 2 different airlines at DXB:

"Dear Sir,

Please be informed Marhaba has got back to us and you can indeed transfer from Terminal 2 to Terminal 1 using there services without a visa and they will help you with the baggage as per the following prices;

a) Interterminal Baggage Transfer Service – Assistance in transferring the baggage between terminals or within the same terminal at Dubai International Airport:

-Speedy clearance through transfer desk check-in formalities
-Baggage transfer from Terminal 1/3 to Terminal 2 and vice versa
-Ramp transfer via shuttle services for passengers connecting between the two terminals
-Rate: AED 225.00 T2-T1 per passenger (for up to 3 bags)

b)Standard Transfer Service – Assistance in transferring or transiting via Dubai International Airport either between terminals or within the same terminal:

-Personalized escort from the arrival flight to the departure flight
-Speedy clearance through transfer desk check-in formalities
-Buggy car transfer within Terminal 1 and 3 at designated areas,T2 -T1 OR T3 visa not required
-Ramp transfer via shuttle services for passengers connecting between the two terminals
-Rate: AED150/- per passenger (Children below 2 years old are free of charge) "