Comfortable sleeping arrangements is at the top of the need list for us. We've had/have all three bed options you mentioned.
Dinette beds typically have thin cushions that even a sleeping bag topper can't make more comfy. And they seem to be sized for really short people. No room to stretch out, unless you can stay curled up all night.
Same for the jacknife bed. Although it may have slightly thicker cushions, it's also short and the cushions are uneven. Never had a good night's sleep on a jacknife bed.
You are correct. An airbed is a pain to assemble, but worth the trouble, especially if your parents invest in some great bedding. It can be just as cozy as your bed at home.
Find a spot for the coffee table, and sleep well.
