Well, how about you try this
Write them a letter to be mailed certified with a return receipt requested and in the letter state that the Screeching is just to much to bear.
State what you have told them about normal outside playing. But that this is like nails on a chalk board and just too much to handle.
In the meantime, call you City/Town Council and get a copy of any noise ordinance. I am unable to locate the local ordinances online or I would get it for you
Read what that says - and you may feel that she is in violation of that. If so include a copy of it in your letter with a request that they PLEASE try to curtail her behavior.
Mail the letter certified with a return receipt requested and see what the response is. Maybe you can get your neighbors to sign the letter to show community support and that it is not just you and your husband who is annoyed by it
Of course, you cannot do anything about any retaliation until it happens. But if it does, you call the police and report it, naming your neighbor as a suspect and show them a copy of the letter you mailed which would show cause
as to why they might retaliate.