So you have five DACs.
Let's simply look at what line-grn has that line-blk/line-org has not.
The input to line-grn is the dac-0:1 DAC. It is used as an output
(so the input on line-grn doesn't really matter.) It is fed with
moderate volume into the mix. Is is not muted, and not boosted.
line-blk seems to have something very similar,
except its input is the dac-4:5 DAC. I don't know
what's causing line-blk not to play. How exactly
are you finding out? Do you have speakers plugged
to each of grn, blk, org?
line-org's input is the dac-2,3 DAC.
It is unmuted, used as an output, but is NOT
fed into the mix in any way.
In fact, line-org cannot be a direct input to the mix.
But you could make line-org an input to sel9 or sel10,
and feed _that_ to the mix ...
... which you don't.
Same as with line-org.
This is irrelevant to your problem, but strange.
Why would you use headphones as an input to the ADCs?
Even *muted* headphones :-)
Jan