Looks like I got data working finally, using the same cut sim.
I don't know what exactly fixed it, but I played around with QPST and DFS without the RUIM inserted, made couple of changes. Inserted the RUIM and restarted, and data just worked.
Summary of the changes
1. Changed the NV MCC MNC to 404 00
2. Disabled Sprint Mobile IP profiles and created a new one and activated with NAI as NET
3. Changed NV Mode to SimpleIP
But the problem now is that the handsfree activation message keeps popping up, I have to switch to Airplane mode and back to remove it. Any ideas on disabling it permanently?