not sure if your settings will help.
I see you want me to start fewer children and limit the maxrequestsperchild but it doesn't look like some script has a memory leak as I don't have a few apache children with high memory consumption, I have heaps of them...
default KeepAlivetimeout is 5 - why set it higher? that will tie my ressources down even more :-(
still, giving some of your changes a try.