The commands you showed etc. is a Linux box. Now it is 2 AIX boxes? They have totally different commands for their LVMs.

Normal behaviour depends. Usually your AIX1 node has exclusive access rights on the storage and so there is usually a reservation on the SAN-volumes. There are scenarios where there are drivers used, that don't handle reservations. Normal behaviour is often to have only 1 node getting exclusive access to your production box. The other node is often just a standby box. But that all depends on how your scenario is set up.
Without knowing that concurrent access from your second node AIX2 is explicit allowed, I would not touch it.

The normal way is to add your LV and FS from the active productive node AIX1.
Maybe you get some more information how your boxes and SAN-access are setup before daring data corruption or problems for the production node AIX1.