Bi amping with two different pairs of monoblocks

^^^^^THIS^^^^^

Unless the power amps are identical volume control will be a problem.

You will get a much bigger bang for your buck by upgrading your OPPO to a modern streamer/hard disk player and use your OPPO to rip DSD files.

Don't even think about bi-wiring, it's nonsense.

Monoblocks fall into the vertical bi-amp camp.  You’re looking to add second set of monoblocks in a horizontal bi-amp scenario.  Level matching between amps will likely be an issue unless both amps have the same gain or a method to adjust gain. As mentioned, that’s a potential issue that will need a solution before proceeding. 

The splitters should be fine.  I successfully use similar splitter to what you linked in a horizontal bi-amp setup connected to a preamp, but my second amp has gain adjustment. 

 You can use this  SCHIIT SYS  to match the levels with the different amps that you are using. Easy- peasy!

https://www.schiit.com/products/sys

Pass XP-32 has independent controls for matching different amps in a bi-amp situation.  It sounds amazing as well.

@yogiboy Check again this will not work

@hk_fan OP has an OPPO the Pass is $17k