I am planning to go back home. The thing is, I am going home alone, but will be returning with my daughter.
Is it possible to get a ticket with one departing, and two return? So we can get seats next to one another since she is a minor.
"Is it possible to get a ticket with one departing, and two return?"
For the scenario you describe, NO.
However, you can make two separate bookings than have the airline (you will have to call unless you do it on the phone initially) link the reservations.
If one of you has status benefits, they will confer to the other for the matching segments. The Agents will also see, more easily at least, you are travelling together.
As far as I know, it is not possible; you'd be getting two tickets. All the passengers on a itinerary are supposed to fly exactly the same itinerary. So you can do it one of the following ways:
Buy one one-way ticket for yourself, and another one-way ticket for both of you. This is what airlines want you to do - and they would love you for that - and this is what would cost you the most (unless you fly low cost).
Buy a roundtrip for yourself and one way for your daughter (or a round trip with throwaway return for her). This is less expensive than above, but will put you on separate tickets. Usually not a big deal unless your flight is overbooked (there you might end up in a situation when one of you is onboard, while another one is not). Also if your daughter is a minor, some airlines would stuff you right away for an "unaccompanied minor fee" during booking (JetBlue does that, for example).
Buy a roundtrip yourself, and either one way for both of you, or a roundtrip for both of you originating from your destination; throw away the returns. This is probably the cheapest way (unless you fly low cost), but it is against airline's "conditions of carriage". The penalties in reality, however, are non-existent.
Note, as stated in comments, that seat arrangement has nothing to do with having both people on the same reservation - it is possible to have two tickets and sit together, and it is possible to sit in different parts of a plane on the same reservation. The only real benefit I see from having both people on the same reservation that if your flight is canceled, you both would be rebooked into the same flight (with different tickets you might be rebooked to different flights), but this could be handled through the agent.
With most airlines you can reserve seats, sometimes for a fee, well in advance of a flight - so just reserve yours and you daughter's at the same time. If you can't do that or fail to do so it is very likely that asking a member of cabin crew will lead to passengers being moved as required to allow the two of you to sit together. Airlines do not like to seat minors next to strangers.