1. Are we setting up the listener correctly?
Listener.ora looks fine


2. Do we need to set up 2 listeners? Do the 2 listeners have to be assigned to 2 different ports or can they use the same port?

Two listeners may work. Start one as oracle and one as neworacle. The problem may be with memory access between different O/S users. The listener process as one user cannot talk to the database proccess running as the other user. (just a guess). For the user starting the second listener set the TNS_ADMIN O/S var and use a different listener.ora file.

Two listeners must use two different ports


3. Is there any permissions issues that we need to look into? Should we just set both "oracle" and "neworacle" to the same group?

You should run two databases out of the same oracle home under the same O/S user OR install the binaries under a new user in a different oracle home.


Andrew
OCP