Good to see that they are "officially" loading I545OYUFNC5 on the phones.
I installed Philz with no problem on my phone via ODIN 3.09 (
Odin 3.09 - unzip this file). Make sure Samsung USB drivers are installed on the PC. Reboot your phone to download mode - Power off phone, Hold Power button and Volume down, on warning screen press volume up to enter Download mode). Open the ODIN 3.09 executable, make sure only F. Reset Time and Auto Reboot are checked, NOTHING ELSE. Load tar.md5 for Philz in to the AP slot - this is equivalent to the PDA slot in ODIN 3.07). I used this version:
Philz Touch Recovery - the latest version seems to be 6.46.3.Connect phone via USB, make sure it shows up on a COM port. If all these prerequisites are met, then click start to flash the recovery. Once the phone reboots and loads normally, grab the latest Superuser - I prefer Chainfire's SuperSu (
Supersu). Transfer the Superuser zip file to your phone. Reboot to recovery. Choose Install Zip. Select the Superuser Zip file. Flash it. This roots your phone and you should be good to go.
Now why would you flash files from VRUAMDK onto the phone. VRU is for the retail variant. If the VRU ABOOT happened to flash then you would have locked your bootloader and ended up with a "retail" device and at the mercy of Samsung to help you out by flashing the original Developer Edition Software back to it. Their call, their choice. For the DevS4, please stick only to phone firmware which contains "OYU", not "VRU" (i.e. I545OYUAMDK vs I545VRUAMDK). You can find OYUAMDK files here on XDA.
Answer 1 to Question 1: At this point I believe you can only run Touchwiz based roms efficiently. Try CM, see if it works. Just PLEASE make a nandroid backup from your custom recovery of your original firmware before you make any changes. That way, in case CM does not work or AOSP does not work, you can roll back to your original firmware. You after rooting you can also dd all the partitions and then keep them in a safe place.
Answer 2 to Question 2: I am not familiar with this situation. As I said, I use Philz and I have never had a problem.
Answer 3 to Question 3: This is a Developer phone. It will allow installation of Kernels and Systems as long as you do it the right way. There are Kernel apps in the play store along with Custom Recovery flashable zip files for both Kernels and Systems.
Good luck taking Samsung to court. This is a developer phone. They sell this phone with the hopes that those who purchase it are already familiar or will eventually become familiar with the device and how to change the software on it. There are tons of threads on XDA which can help you. Read, read and read again. Make sure you understand before you go about making changes or flashing software - especially software not intended for the Developer Device (i.e. firmware containing the three letters VRU versus firmware containing the three letters OYU). Ask questions - we are here to help. I am more than willing to help, but please do the research before hand. I was a n00b once and even at this point I am not a master of this stuff, I learned by asking questions and also by trial and error.
Good luck.