Duntech PCL-3 on-wall will xover at 80hz make easier to drive

You should see about 2.9 to 3.3 ohms DC with nothing connected to the drivers. You'll need to remove the wires from the amp to the driver.  Again, don't mess with the crossover. If you feel they are lacking in power after adding subwoofers, you could replace the amplifiers with 100 to 200 watt amplifiers.  The bigger amplifiers will need to replace the existing amps and be external. Post more info if you have specific questions.

Are all of the speakers in one room or different rooms?

I owned Duntech Princess speakers for 19 years, the longest I've kept any component.  With that bit of experience I can offer a caution.

My Duntechs were rated 90 dB efficient and the manual suggested 100 wpc normal and 200 for "maximum musical enjoyment".  The best performance I experienced was driving them with Parasound JC-1 mono blocs, rated at 800 wpc into the 4 ohm load.  So I didn't consider them to be as efficient as claimed.  I suspected two reasons.  First, the load actually dropped below 3 ohms in the bass range.  Also it had a very complex crossover to achieve the time and phase cohered Dunlavy considered to be so important.

I realize the PLC-3 is much smaller but in my experience all the Duntech models liked power.  His later DAL designs were apparently more efficient.