Hi,
Yes, the MSE license is transferable to CMX and both versions will be fully operational. No, you will not need additional AP license to operate both systems. Since there is not a direct upgrade path from MSE to CMX, Cisco CMX folks suggest running both versions in parallel during a transition from MSE to CMX 10. Then, only when CMX is stable, to retire the MSE system.
Thanks for the question,
Matt