I am running about 12 databases on one server totaling 1.5TB - all with TDE enabled. The total cpu cost is about 5%.

The problem with enabling Encryption on all of them via different jobs is the encryption sometimes gets hung up and will show 0 in percent_complete and also show that it is encrypting. This happens from time to time and requires restarting the encryption for that database (disable re-enable). Unless a long delay is ok, you might want to monitor the progress.