cartridge/preamp volume issue

It's not an impedance issue. That kind of problem is more typically a gain mismatch issue. However, the gain and sensitivity specs on all of your equipment look pretty conventional and compatible. I'd suspect that either you have a bad connection or cable somewhere (although that would seem not to explain why both channels have the problem), or something isn't working properly.

I'm assuming that you have the gain selector switch on the rear of the GCPH set to its maximum position. If not, that could certainly account for the problem.

The only impedance spec that looks a bit atypical is the Blueberry's output impedance of 3.5K, which is higher than usual. That will not affect volume significantly, because it is still very small in relation to the amp's 100K input impedance, but it might result in some upper treble rolloff if the interconnect cable is long and/or high capacitance.

Regards,
-- Al

You could also try the MM input of your BB Extreme to see if you can get any volume out of it. With 58-db of gain, you should get some output.

That's an excellent idea, to help isolate the problem. But in case it's not clear, he means to try the mm input of the preamp WITHOUT the phono stage being in the path (you don't want to have two phono stages in series). I'd expect doing that to result in some amount of background hiss, but with volume approaching reasonable levels.

I haven't looked to see what load impedance is recommended for the Lyra Dorian. See what is specified for it and set accordingly as a starting point (perhaps re-adjusting later for best sound quality), but in any event the load impedance will not affect volume significantly, just the sonic character of the upper treble.
And yes, I'd expect the 66db gain setting on the GCPH to work best with that cartridge, although 60 might be acceptable as well.

Regards,
-- Al