My review is nearly done, all your questions will be answered then.
Btw, PP6 is a CIEM earpiece, DAC+6-amp combo. DAC is based on Algorythm Solo from what I heard, bi no tri-**** 6- amping is done by 6 different amps and active crossover filter is done by a DSP from my guess.
I don't think any of the above matters because a) low, med, hi have really good isolation and definition, I think the active crossover works to a degree, b) DAC amp is definitely better than my F7 + O2 combo, c) There is no- at least to me- noise introduced by tri-amping and the gain filter, so all's good.
TL;DR: It sounds fantastic, but wait for my review.