Just signing the apk isn't enough(easy to automate). I've told you already.Boot animations can be changed on other distros,
But to change cursor we have the replace the framework in /system/framework/framework-res.apk. To change it on other distros we have to make frameworks for all other distros, unfortunately this is an limitation of android. But you can make cursors by yourself and put in the framework-res of the distro you want, and also sign the apk with uber signer or else it wont boot.
Hope that explains
But if you have some other popular android x86 distro tell us, and we will make cursors for it.
You will need to disable-sigcheck by patching decompiled framework(services.jar and a few others) smali as well .. which is hard to automate when it comes to patching multiple android-versions from a single patch-set.