You can use global views to check for a particular PDB. Each dynamic view is having the column CON_ID which his corresponding to a particular PDB.
From the view cdb_pdbs you can get PDB name con_id:
sql> SELECT PDB_ID, PDB_NAME, STATUS FROM DBA_PDBS ORDER BY PDB_ID;
The queries which you are using to monitor performance stats for normal database you put additional where clause to have CON_ID to get similar output for a particular PDB.