We don't all sit down together at dinner either. We don't have the room. If we are home together on a weekend we do, we'll sit outside together on the outdoor setting, but not inside.
there's nothing wrong with baked beans and scrambled eggs! you could even make some spinach and cheese scrolls or something to serve them with (or as a snack).. and having a protein based meal at night is fine, as that is when your body is rebuilding muscle.
Can you ask them what they like? I know Oliver likes tuna pasta, Jordan likes burritos, Gabriel likes sausages, Julian likes instant noodles, Lysander eats anything.. So I rotate through a couple of those each week.