Biamp question

I guess I won’t know that until I try it. On the crossover question, I want to get a crossover that already matches the crossover points of the speakers.

External XOs are adjustable. I use the First Watt B4, Marchand makes them, and several other manufacturers.

Typically on these XOs there is one input (connected to your preamp out), and two outputs connected to your Parasound and Rouge amps: High frequency and low frequency. So 20 Hz - 20 KHz (nominally) goes from your preamp into the XO and you set what range of frequencies comes out of the LF and HF outputs. So you can set the outputs to match the XO points the speaker manufacturer designed.

Note that this discussion about external XOs is only if you will not be using the internal crossovers built into your speakers.

Honestly I am not sure how to use the built in crossovers of the speakers. Seems the connections would be different. Please excuse my ignorance on this topic. 

I’ve never used internal XOs (I built my speakers without XOs), but my understanding is that they are in the speaker, so if you connect to the speaker terminals you will be using them.

So you could just connect the Parasound to the LF terminals on the speakers and the Rouge to the HF terminals, adjust the Parasound to match volume, and you’re done.

But I've never done this so if I were you I'd wait for someone else to confirm

Now I’m thinking/wondering if you need to have 2 amps that are exactly the same to use internal crossover wiring method. 

I have a pair of custom speakers that are very similar in design to the Legacy Focus using Eton drivers on top and Peerless 1259 12" woofers.  The Peerless are a bit less efficient so bi-amping is pretty much a necessity.  I've used the internal crossovers without issue.  Since the bass drivers are less efficient, I've always used separate volume controls for the satellite section (tweeters, mids, midbass drivers) and the woofers.  

My sources have all had built-in volume control so that has been the main volume control while the bass section has either been an integrated amp with its own volume control or a separate preamp to drive the woofer amp.  Currently my DAC is an Audio Alchemy DPA 1.  I run the balanced outputs to a Red Dragon S-500 driving the satellite section while the RCA outputs drive a Kingrex PREference preamp into a D-Sonic M3a-800S.  This allows me to adjust the bass output to suit my taste.  The Kingex is fairly cheap but is quite transparent and articulate in the bass range so works very well in this application.  You could try biamping first with your 2 different amps using the 2 pairs of outputs from the Rouge preamp and see how that works.  If the bass isn't satisfactory, then you could do as I've done and ad another volume control device between your pre and the bass amp or perhaps you could do that from your source to avoid running the signal through 2 preamps.