The 4EXT themes are to be used on madmaxx82's brilliant 4EXTRecovery which can be found here. Should you want to uninstall any theme just flash this 4EXT Theme - Uninstaller in recovery.
To download click on the preview of your desired animation or theme and flash in recovery
If the flashable .zips are not compatible with your rom try manually extracting bootanimation.zip or downanimation.zip from the flashable archives and manually copying them over your original animation. Make sure to set the permissions as shown below.
To push the splash1.img use the executables (many thanks to roboprint for preparing these) which are provided in each .zip or alternatively, connect the phone in USB debug mode, go into the bootloader fastboot and type the follwing into cmd;
- fastboot flash splash1 splash1.img
- fastboot reboot
Many thanks to Whiskey103 for the file hosting.