I know Mexico City airport quite well. Pass thru there often.

– There are basically NO activities for children.

– The airport is modern, not huge, and crowded

– Aeromexico Airlines has good service (as most upscale things Latin American)

– You most likely will take a shuttle to the terminal on arrival. So the short answer is “yes” you will need to find a different terminal. It is not overly difficult, especially if you have plenty of time.

You will find English is widely spoken in the terminal. I would also add please keep track of your valuables and children at all times.

If you have extended layover there are some incredible cultural sites in Mexico City. Just be careful. Use airport taxi, etc.

And one other thing, thank God you have time. You will have to pass thru Mexican customs. Be patient.