.snip.
Aside from the motives of the forkers (honorable or a get rich quick scheme) what should LTC owners do?
They do nothing more than "a get rich quick scheme".
.snip.
What to do if you have your Litecoins currently on an exchange?
You can't claim it from exchange if the exchange itself doesn't credit you. You need to withdraw it, wait for the fork snapshot and then deposit it back in the exchange, it you want.