Alyssa and Shannen, yes, but Holly isn't desperate, the only reason she hasn't had any real work for the last 3-4 years, is because shes taken time off to actually raise her children, unlike alot of other actresses, who would just hire a nanny to do so.
As for the movie happening, it could happen, but if it did, it'd be a network such as fox that would grab it, because the network the show was on couldn't give a rats ass when it came to seasons 7 & 8.
As for Shannen and Alyssa, last i heard their fued was over 2 years ago.