It's been my experience that macaws are either very skittish of little kids, and keep them at bay, or they really enjoy playing with them, and are super curious about them.
Generally speaking, big beaks and little kids are probably not a good mix.
In my opinion (and I have worked with ALL of the big macs), the best big mac temperments around kids would be: Hyacinths, Greenwings, Red Fronts, and Blue Throats, followed by B&G's (which can be high strung around young children in my experience.)
I would stay away from the beakier species: i.e. militaries, Buffon's, and especially Scarlet's. They tend to be short tempered and communicate with their beaks first.
"Issue Macs" and young children, in my opinion would be something I would be reluctant to recommend.
Frankly, the best macaw breeder in the US right now is probably Wendy Craig, and she socializes her birds to the Nth degree... IF I WERE IN THE MARKET FOR A BIG MAC, THAT WOULD BE THE PERSON TO CALL!
I'm not the first person to suggest that Wendy's the best. Ask around. And she's local here in Texas.
Where are you in relation to San Antonio?