Would it be possible to implement a mechanic to force an animal companion to move stealthily if the master is attempting to do so.
For instance, if I were to take the panther form and move stealthily, I would expect that a panther AC would instinctively do the same with or without a command given.
Just quickslot yourself a:
/c stealth a
Command.
There is no hook in place for "when stealth mode activated" and thus, we cannot follow up with a "then force companions into stealth mode".
You can just quickslot the new companion/familiar stealth command and train yourself to remember.
IMO it would be also a bit annoying at some point, if YOU want to be stealthed and the familiar/companion to be visible :p
Is perfect as it is!