Closing a channel in Lightning Network
The first three scenarios are indeed possible, the last one is identical to the second.


This is called a collaborative close. It has the advantage of using a lower on-chain fee since the transactions are not time critical and the users get their coins back immediately (no dispute time).
If the other node is unresponsive (offline or doesn't sign a collaborative close), you can do a unilateral close. The downside of a unilateral close is that the closing party will have their funds unavailable until the dispute is settled (usually about 24 hours) and higher fees are leveraged since this is a pre-signed transaction that is time-critical to get confirmed.
This is called a breach-attempt, and is the reason for the dispute period above. The breach is basically publishing an old unilateral close transaction, and it needs to give the counterparty time to react and punish the breaching party.


So in all cases well-behaved parties get their funds back, the difference is just in how long it takes.