Is it possible to spend an output that hasn't yet been confirmed? From something I noticed in this thread: Unconfirmed BTC

MtGox will send a transaction to spend one of the outputs of a transaction that hasn't yet been confirmed.

Is it possible for both of the unconfirmed transactions to be in the same block (in the right order)?
Yes you can spend an unconfirmed output.
You can see this in MultiBit if you:

1) Send some bitcoin from one wallet to another.

2) In the wallet that received the bitcoin you can spend it. Because the bitcoin came from one of your previously confirmed transactions, you can trust it even though it is unconfirmed.

Of course, if you spend a transaction that is unconfirmed and it never confirms, then your child transaction will never confirm either.