I fail to see the need to upgrade. The drivers used in your front channel speakers are excellent and if you are using the upgraded crossovers and a sheet of No Rez they would be hard to beat. Your speakers are not your limiting factor right now. If I were looking to improve the sound, I would:
1. Subscribe to a high quality music service such as Tidal or Deezer. Pandora is giving you lossy files.
2. You are using a lower-midline Marantz receiver and an outboard amp. I would sell the two of them and invest a little more money on a Marantz SR 6012. If you do this, I would also add two sets of small Atmos height speakers.
3. Replace your subwoofers. For my money and your setup, I would look at a pair of Rythmik L12 subwoofers.
A pair of higher end stand mount speakers from the manufacturers you listed are expensive ($1,500 - $3,000), and in the context of your system you can improve the sound much more in other areas for the same money. Hell, for $3,000 you could build a whole new great sounding small system to sit alongside your HT rig.