If I drop off kids with tix for a concert can I hang out in the building at a restaurant or bar while I wait? Is there a place to hang out inside and before entering security area?

There are plenty of places with public seating to grab food and drinks right before the security checkpoint

So the area has no lack of bars and restaurants, but MSG has no actual waiting area. I personally go to the New Yorker Hotel which houses the Tick Tock Diner, where I go b4 a concert. U might have an issue tho, as shows run hours, and u need to drop kids off around 7pm, and shows often don't get out till 11pm, typically.

To be honest, I don't remember so well, but it has some places with drinks and tables, no chairs as I remember. Hot dogs, nachos, beers, pizza is what I remember.

No