Transferring a plane ticket?

My family and I are going to Florida on the 27th October with my uncle (There's 5 of us - my mam, dad, brother, uncle and I). Unfortunately, my uncle isn't able to go anymore, but we have someone that could come in his place. We're flying from Dublin-Orlando with United Airlines and the ticket is an economy ticket. I know there's a fee for name changes on a ticket. I also know that it is generally the price of a new ticket. Our ticket originally cost each but now would cost to buy for the same flights. I was just wondering, If we wanted to change my uncles name to my cousins name…
1. How difficult is it to do?
2. I seen that you can separate travellers on united airlines so that they have their own, new reservation for the flight. Can you make name changes if you do this?
3. Would I have to pay or towards the name change?
4. Does it make it any easier that we booked through Skyscanner and not directly from United Airlines?

United doesn't allow transfer of ticket. If the other person wants to go they will have to buy a ticket in their name. Your uncle's ticket still has value if he cancels prior to flight, if he doesn't cancel and is a 'no-show' then the ticket has no value. The value can be applied to another ticket on United only, and any change fees that apply. He doesn't need to rebook something to Florida, it can be anywhere they fly.

United does not allow you to transfer the name on a ticket. If your uncle can't travel, and does not have travel insurance (or a reason covered by travel insurance if he does have it), then he loses the value of that ticket. He might be able to get credit toward future travel by cancelling and paying a cancellation/change fee, but that will not likely be something that you could use toward another traveler. It would be credit that he could use for himself in the future, but they often won't let it be applied toward the travel of another passenger. If you want to bring another traveler, then they have to purchase their own new ticket in their name.

For future reference, it's usually harder to make changes and manage your reservation when you book with a third-party site such as Skyscanner. Booking with the airline is ideal, and airline prices will not differ from other sites. But in this case, it doesn't make a difference because you can't change the name on a United ticket, period.

Not gonna happen - United, as well as most other airlines, do not allow name changes/airline ticket changes anymore

You're asking the wrong people. You're going to have to call united anyhow so you should have called them first as they are the only people who will give you official information. Ibsay official rather than correct because the answer you get depends on who you talk to at united but either way, its official.

Your probably going to have to buy a new ticket. United gets pretty picky with this, if you ever are in a situation where you know there might be an issue come up, buy the more expensive ticket so that you can refund it

There's no point in asking anyone except the airline. ONLY the airline can give you an authoritative ruling on what is possible for YOU, with YOUR kind of ticket, in YOUR situation.

Remember, just asking doesn't commit you to anything. If they say Yes, you can do that but it's going to cost a zillion dollars, you can just say 'Thanks, but I think I'll leave things as they are'.