2) once S-off you have a few options here:
a) take the 4.4.4 stock OTA before you flash TWRP or make any changes to your system
b) use dottat's RUU.exe to update to 4.4.4
c) flash the 4.4.4 firmware from Tigerstown's thread in fastboot.
3) No matter what method you use, eventually you will have to flash TWRP in fastboot. Flashify needs root and you don't have that until you flashed SuperSU in recovery. Once rooted you can use Flashify to flash recoveries if you want. I would recommend you use fastboot.
A) So if I choose option C, can I just do the SD card method to update firmware? I've always done it that way with my phones and had no issues.
B) Out of curiosity more than anything, why can't I flash TWRP before updating to 4.4.4?
Thank you so much for the assistance! I'm going to be working on his phone in about an hour.