My only concern is with the impedance of the Polk LSiM 705, which is really an unknown, due to Polk basically lying about the impedances of their other LSiM speakers. Take a look at this:
https://www.soundandvision.com/content/test-report-polk-audio-lsim-speaker-system-page-3
They measured the impedance of three speakers from the LSiM series, all of which Polk claims are 8 ohms, but they are not. Unfortunately, the 705 is not one of the ones measured there, and I have not located any reviews in which they are measured. The tower speaker that was measured with a 2.8 ohm minimum impedance is the 707, as you can see if you look at the first page of the review:
https://www.soundandvision.com/content/test-report-polk-audio-lsim-speaker-system
Sound and Vision is even being a bit loose with their nominal rating of 5 ohms. If they followed the standard that engineers use (as opposed to marketing teams which basically don't care about what happens to your gear when you hook up something that is mislabeled; indeed ruining your gear may be a benefit to them, as they can then sell you more gear to replace what is ruined):
would give a nominal impedance of 3.22 ohms (because 2.8 x 1.15 = 3.22). Of course, that would normally be rounded, but to the nearest whole number would give us a proper rating of 3 ohms. Keep in mind, Polk calls this an 8 ohm speaker.
The impedance matters because a lower impedance tends to put a greater strain on the amplifier, requiring higher levels of current from it.
As for the sound quality, the LSiM series are pretty universally liked for that aspect, so if your amplifiers would be happy driving them, then they should sound good with your gear.
If you never listen at high volume, and you do not hook up two sets of speakers, you can probably get away with the LSiM705. I say "probably" because we really have no idea what impedance they really are. Judging from the incorrect ratings of the other LSiM speakers, it is likely much lower than the rated 8 ohms.
