Let's see...

Smokey the Elder was Keith's tutor on his Series 7 exam, so I guess that would make her a stockbroker.

Mobius is a tax preparer. When I'd do my taxes manually she had to audit them.

Diva is an acoustics tester. She's constantly meowing to test the acoustic tiles in the kitchen.

Pixel is a groomer. She's always grooming the other cats' heads.

Diamond is the table and lamp inspector.

TicTac is the token male cat.

Smokey the Younger is the bed tester. Whenever I bring home new cat furniture she has to check it out.

Bosun is the enforcer. She always keeps the other cats in line.