Here is new schematic. I hope it is schematic of working electrical circuit because I have done many hours of work for it.
Edit. I found few mistakes but nothing super big. I corrected them.
Edit2. Thanks to Sparkfun irc channel I found out that my pull up resistors are connected wrong.
Here is 3d rendering of PCB. 
I will use connectors that have lock feature.
Edit. I added decoupling capacitors to mux chips as I just learned about them.
I have redesigned WS2811 PCB. I did incorporate rotary encoder to it.
Edit.
Oh yeah. I forgot that I have to fit 16 of these pretty close to each other. I need to redesign it again.
They need to be so close in fact that it is smarter to make one big PCB instead of many smaler ones.
Here is schematic and picture of 3d model of new PCB. I will use 2 of these.
There will be 8 rotary encoders on backside and those 16 connectors are for drumpad leds and force sensitive resistors.
Big row of pins is for connections to teensy board. I will redesign it so that it has 4 rows of headers. 2 rows for each FSR/led/Encoder PCB.
I have not made connections so there is no tracks in picture. I will make mounting holes later.
It is done. I had to make board little bit bigger so that I can fit tracks. I hope there was no mistakes in schematic. 
Now I will go and redesign that Teensy board.
Edit.
Oh and I made little change to schematic. because of this.
I have noticed one mistake in that fsr/led/re PCB schematic.
I have connected FSRs to GND and not to analog GND. I will go and re do whole PCB. While I am at it I will transfer pullup resistors to PCB that Teensy is connected. I hope I can finish these PCBs today and this is last iteration of PCBs.
Here is another PCB. I realy realy hope that there is no mistakes and I can send files to OSH Park soon.
I think that I go with dirtyPCB for PCB manufacturing as it it cheapest I have found. I will check schematics again few times on different days just to be sure that there is no mistakes before I send files to dirtyPCB.
You are really doing a nice work, @Aleksi!
I’m very curious to see your zynthian finished 
Regards,
Thanks alot! You can belive me I am also. 
I knew that there is still some mistake somewhere. Left side connector is from FSR/LED/RE PCB and right is from Teensy PCB. Pins 36 and from 1 to 19 are OK everything else is upside down. 
I have redone PCB that has rotary encoders, connectors for leds and force sensitive resistors.
As you can see I have moved connector to left. This is so that I can put PCB that has Teensy connected to it left as possible inside synth body. Before I would had to put it more to center and it could take too much space. Maybe it was good thing that that connector had pins upside down.
aleksi , so I know your in finland, what do you do in finland
this project will cost atleast 2 of your arms and maybe one of your legs , finland prices
id like to keep in contact with you as I’m in finland also, I’m a brit though and moved here a long long time ago
I guess your from Russia going by your name ?
Mosty I waste time. I dont have job or school to study in. I am trying to get inside univeristy to study natural sciences, mathematics or compuer science but it is hard as I have only car mechanic studies behind me. Maybe next year I get in through Helsinki universitys programming MOOC.
It would be nice to stay in touch as I dont have lot of friends.
Why did you move here? Because of work or some lady?
No, I am fully finnish.
I think that I have found better power supply than that one I posted before as you can buy one of these ready to use. Here is link to it. It is called UPS PIco and there is 2.5A and 3A versions available. You can use LiPO or PLiFePO4 batteries with it.
and you really think, that the zynthian will be less than 900EUR? 
I am not sure any more. 
I would concentrate on this tenzy board first.
Let’s make that board and we enhance the zynthian software so that it can handle more than the known 4 knobs.
Baby steps is the secret
or what is your opinion, @jofemodo?
You are right. I should concentrate on it first and get it working before I think about battery power.
