I have a trip planned and the flight does not get in till 12:25am. I will have my family with me. Will someone be around to hand us the keys to a reserved vehicle if we reserve a vehicle ahead of time?

I wouldn't count on your car being ready when you arrive. I'd prepaid and selected a class, but still waited quite a while. Give yourself extra time to be safe, at least 30min. If the weather is poor, maybe even longer.

They are open, but unless you join fast break program you will still have to go in and wait in line

You can call them and tell the time.. We also reached around 2 am and there were people.. In fact there should be staffs in the office..

I believe they are open 24 hrs