Mid-2012 MBP with 27" Cinema Display SCREEN GOES BLACK WHEN USING USB PERIPHERALS IN DOCK

I haven't been able to find any straightforward answer as to why this is happening and it's becoming one of the most infuriating things in my life, impeding my workflow and costing me unmeasurable time in waiting, rebooting, screwing with cables, etc.

I use my MBP as a DAW for multitracking live audio events to ProTools through a digital console where I work. Here's my gear list that I use every day:

Mid-2012 MBP - Yosemite, 8GB, i7 quad 2.5, mechanical hd

HengeDocks dock for my exact model machine - has set-screw jacks for CinemaDisplay power, Tbolt, FW800, USB, USB, SDcard, headphones, etc

USB wired keyboard

Anker 1x4 USB3.0 hub - I have a TimeMachine 1TB drive, 3TB project backup drive, audio interface and MIDI I/O or PT iLok, depending what I'm working on

Magic Mouse (BlueTooth)

Here's what's happening:

SCENARIO 1 - I insert the CinemaDisplay (cD) power connector and TBolt plugs into the dock, tighten the set screws, close the lid of my MBP (already logged into Yosemite & linked with MagicMouse [mM]) and stick the MBP into the dock... everything comes up on the cD and I can go about my day. At this point, I can plug the USB hub into the back of the cD and the system sees the hub & all peripherals listed just fine.

SCENARIO 2 - Install cD powercon, TBolt connector, USB3 hub, USB keyboard into the dock, close the lid on MBP (again, logged in), insert into dock... cD comes up, looks great for about 15 seconds then goes completely blank. No response from key presses, mouse clicks, threats with a hammer, etc. Then, of course, I have to yank the MBP out of the dock, which hard-disconnects the external drives (backup and TimeMachine... good for them, right?) and causes the MBP to flake, thinking it's still in the dock, then not, then logging me out & requiring a password (not a big deal- I deal with copyrighted stuff, so passwords aren't the issue).

***EVEN IF I DO NOT PLUG THE USB3 HUB INTO THE HENGE DOCK, THE cD STILL GOES BLANK AFTER 15 SEC... IT ONLY SEEMS TO LIKE THE TBOLT AND POWER... NO OTHER PERIPHERALS (fw800, USB, etc)***

It seems like the MBP freaks out when the lid is closed and there are USB/FW peripherals plugged in while using a secondary TBolt display as the main output... seems stupid... if I need a closed-lid dock, the MBP shouldn't care what I have plugged in while the lid is closed. I had the same issues with Mountain Lion & Mavericks and now it's being repeated with Yosemite.

My goal in this exercise is simply to free up the USB jacks on the back of the cD for two reasons - #1) from time to time, I have extra things to plug in and I don't want some massive USB 1x8 hub on my desk... looks stupid; #2) the bottleneck created by plugging in the hub to the back of the cD (another hub via TBolt) almost triples the time required to back up/copy files. I move files from system drive to backup drive & back VERY often due to the nature of my job... speeding up this process would greatly improve my efficiency in the matter. Why would Henge create a dock with all the jacks on it to allow someone to plug into a cD that won't frickin work with said cD? Every other dock I've found makes the user stick the MBP on a slanted, goofy-looking stand and have the lid open or something dumb like that... what I have is the setup I need... just need the USB stuff to work while lid is closed and everything from powercon & cD to USB3 hubs will work without making the cD freak out.

Any ideas out there?