As far as I'm concerned, the Chameleon IntelAzulFB option is irrelevant/non-applicable with Yosemite. It was certainly required with previous OS X versions and could be replaced by a DSDT injection of the appropriate ig-platform-id. For instance:
Method (_DSM, 4, NotSerialized)
Store (Package (0x06)
0x16, 0x04, 0x00, 0x00
0x06, 0x00, 0x26, 0x0a // FB #12, replaces default FB #7 0x00 0x00 0x26 0x0c
DTGP (Arg0, Arg1, Arg2, Arg3, RefOf (Local0))
In your case, boot option IntelAzulFB=12 is a simple unnecessary duplicate of boot plist entry InjectIntel-ig=0x0a260006.
In Yosemite, you have to patch (plist + binary) the Azul framebuffer + HD5000 kexts. You can then retain the original mobile Intel HD 4600 device id 0x0416 instead of faking Desktop Intel HD 4600 0x0412.
I'm personally using Chameleon on my Dell E6440 fitted with HD 4600 GPU. You can read details about the IGPU support process here.
You also have a cache issue, hence hanging when booting without (using -f flag) but no QE/CI when you boot with. I have the same issue when attempting to boot without cache. To rebuild your cache, use the following Terminal commands:
sudo touch /System/Library/Extensions
sudo kextcache -Boot -U /