In my experience at several RyanAir airports, no.

Often it's the same staff that arrive, check people in, and then reappear at the gate to board you. It's all done as part of an operation to have fewer staff costs. So them being there the night before? Maybe if there's another RyanAir flight at the same time. But most airline in my experience also won't check you in the previous day. I've also tried a few times ;)

Presuming it's this one, this link on sleeping in airports may help.

In my experience at several RyanAir airports, no.

Often it's the same staff that arrive, check people in, and then reappear at the gate to board you. It's all done as part of an operation to have fewer staff costs. So them being there the night before? Maybe if there's another RyanAir flight at the same time. But most airline in my experience also won't check you in the previous day. I've also tried a few times ;)

Presuming it's this one, this link on sleeping in airports may help on where you could at least rest your head.