If you're rooted you can get rid of the Vodafone boot animation in multiple ways. Either replace it with another one. Or add a single line of code to build.prop to disable it completely. I don't think anyone has gotten anything aosp to boot or cm12 but KonstaT has proven that modified system and boot images can be built and flashed and work. ZTE have possibly just done something screwy with this device possibly something minor but until we know what it is we won't have anything booting up except modified stock ROMs.