We've been to Sci Fi many times and a few of them was with just the three of us - me, husband and son (or varying ages through the years). Kids usually just sat by himself and we could easily talk to him if we wanted. Mostly, he just said what he wanted, he or we would tell the server and then we'd have a nice meal. But we still talked during the meal.
Best time, though? Was when we went back with our now grown son with kids of his own. We were six in the car. Two grandkids in the front set, my husband and me in the middle one and son and daughter-in-law int he back seat (yes, we did make jokes). My husband and I got to listen to our two grandkids in the front seat consider and choose their meals on their own and then each order themselves. One of the best family meals I have ever had in my life.