One bird is possessive of your husband, then that will pretty much be the way it always is. So watch yourself if you get close to your husband and the bird, they get ornery and will lunge.
The screaming is a common thing with parrots, #1 reason for rehoming. Things to avoid is, running to them right away, give them exercise which could be a spray bath or wing flapping, only approach when they are not screaming, sometimes contact calls are good (say words they like to say back to them, so then they say that instead of yelling).
Diet, cheap ways to improve their diet is search on here for chop recipes, it is pretty much things you have in your house. Or just chop up veggies/fruit in to small pieces and offer every day, even if they don't eat it. Mix some into their regular diet too. Common foods that birds usually like are walnuts, almonds, grapes, apple, carrot, oranges, oatmeal, try a little of everything if you have it in your house. Coconut oil isn't that expensive anymore, they sometimes like to lick it right from the spoon. The ideal diet is fresh, so if you are changing it, you might want to slowly go that way. Warm oatmeal with banana is nice too, they like spoon feeding, it will remind them when they were babies. Fresh is less expensive the pre made mixes if you have time.
You will read so many things about parrot ownership and all the different things you need to do, don't worry about all of it, focus on the important things, diet and adjusting to the new environment. You are always learning new things as a parrot owner and you may start to think we are all fanatical lol and we are.
Parrots usually love to hear kids songs with their names in it
Old MacDonald's Farm is a favorite. Peek a boo is a fun game, the macaw will love.
The toy suggestions are great, another one is hide a nut in a paper towel and knot it, they like that.
Last thing, my god, I admire the both of you for taking on such a big task, not knowing how to care for them! We were all new at one point
Keep asking! Keep reading!