Hi Toleda-
There does appear to be problems with the X99-E WS that may not be fixable. Something weird I have come across in testing, points to a problem with ethernet. If I attempt to view a video on youtube and choose lineout option under sound settings it immediately freezes the video and brings up a spinning loading wheel on the youtube video. Its reproducible. To date I haven't come across anybody getting the audio to work, outside of using USB.
Some other things of note.
Multi-beast Method
I have tried the multi-beast method to install fixed audio with the following options below selected, and get a fatal error from multibeast when Realtek1150 drivers are attempted to be installed.
Realtek1150
UEFI-support
Audio_ID 1
(The X99-E WS has 7.1 surround options so I am not sure if there are more options necessary)
Toleda Method
I have tried your method as well, and have gotten the furthest with it. The success is limited to getting the drivers to post, but no audio. Your method is the one presenting the youtube problem. I checked the drivers and they are recognized correctly as Realtek1500 and IOReg/HDEF/layout-id/<01 00 00 00> is correct. A second thing I notice is one of your scripts are placing a folder on my desktop labeled 10.10.4_realtek1500 with an AppleHDA.kext and orig-AppleHDA.kext file. I am not sure if the script is supposed to be doing this, or if it signifies the problem. All in all your method is doing the best work for it, just need to figure out if a DDST export and patch can fix the problem (and how to do this) or if it is beyond fixing.