Hello, and welcome to the Parrot Forums family!
In my opinion, I'm sorry to say, the situation as you've described it would be far from ideal for a macaw. The general chaos of a kindergarten classroom would likely be terrifying for most birds as their constant. The stress would be very high, which could lead to varying health issues. As to your individual questions...
How are macaws with kids? Depends on the individual macaw, as each has its own personality and upbringing. Given the environment that you propose, chances are that those macaws would not be good with kids.
Do they not like loud noises? Generally, no. Sudden loud noises can be frightening and stressful to them. Though their tolerance for said loud noises would vary depending on their upbringing and personality.
Do they not like constant attention while in the cage? Constant can be stressful, depending on the bird. I know you're seeing the word 'depend' a lot, but parrots are highly intelligent birds with great variations in terms of personality. But as a general rule, no, a bird would appreciate being able to escape constant attention if even for a little bit.
Do they need to be out of the cage alot? Yes. Several hours per day.
Can they be left alone over a weekend if there are two of them? Assuming that you mean left largely alone, with someone coming in to provide them fresh food and water at least twice a day? Then yes, it's possible, once in a blue moon when absolutely necessary. But in the way you likely mean, leaving them alone every weekend? No. Macaws are social creatures. Again, a kindergarten class environment is just not a good place to raise macaws.
I really appreciate you coming here to ask these questions before just blindly accepting the offered macaws. Shows a lot of consideration on your part. I'm hoping the best for those two macaws and their search for a home.