I'm using the version of TWRP found here. Scroll down to the Odin Packages.
New recoveries for new phones that won't mount storage!! - xda-developers
Also, when I did my initial wipe, I wiped just about everything. I did a factory reset, then went into advanced and wiped dalvik, data, and cache. You can wipe internal too. Just make sure you make a backup of your internal and keep it on a computer as I mentioned earlier. These AOSP ROMs make duplicate folders on internal and the sd card both.
You can try skipping the Piggyback.zip step because I'm pretty sure 4G isn't going to work with these ROMs. The Boost xml file should fix your 3G and get MMS working.
I don't have 4G in my area so that's something I can't test.
I also had issues with the Vanir ROM. I had random freeze ups and random reboots.
I may end up just removing it from the list.
By chance, did you try the link iMaYG posted?
I wish a few others would test it out so we can get more input on how the ROM acts on their devices.