Yay! Thankx to all helping answerers! 
How could I oversee that - !?!?
That is what I wanted, and it works. 
Yippieyayey!

Sorry we jumped down the wrong rabbit hole at first on you.
 
A couple quick notes with this situation which can save you some future work -
 
1) The outputs inside of ARIA will revert if you load an Ensemble, but they will stick if you just replace instruments of an already loaded Ensemble. After you set those to all 16 stereo channels, save the Ensemble (left click in the Ensemble name area) inside of ARIA itself. You will want to repeat this if you swap instruments around and may use that Ensemble again in another project.
 
2) After you have done all of the work for an Ensemble and routed it inside CbB, be sure to save that as a track template (and verify it inserts properly). This was mentioned earlier in the thread, but you will want to save that track template with ARIA configured properly as well so that inserting the track template comes up "fully functional."

There is a last remark to this, but it seems a very important detail.
In the Aria Player (Mixer page), you NEED to turn all the sends down to ZERO. Otherwise an instrument that is e.g.  routed to output 5 / ouput 6 (stereo) will also come out at output 1 / output 2 (stereo), so if you apply some fx to out 1 / 2, it will also affect the instrument that you routed to out 5 / out 6. No busses you use in Cakewalk itself will help. I tried that first. 
You will only have a clear mix if you turn ALL sends in Aria Player (Mixer page) to zero. (The sends you are using in Cakewalk will not be affected by this, I also checked that setting.)