Rhino would strongly consider joining the ECW brand if WWE offered him enough money. Rhino's contract with TNA will be expiring in July. TNA is trying to get him to sign a long-term contract.
Raven is currently under a three-year contract to TNA, so he is obviously ineligible to sign on with WWE for the ECW project.
Team 3D are currently under long-term contracts to TNA as well, so Brother Ray and Devon are not candidates for the ECW relaunch. Also, friends say that Brother Ray cannot coexist in the same lockerroom with Johnny Ace.