Freesync is adaptive sync.
What that means is that instead of your monitor always running at one refresh rate (144hz for the one you selected, as your primary monitor, for instance), and then displaying frames when the GPU sends them, which can cause tearing or stuttering when a frame is drawn halfway through a screen refresh, etc, it instead syncs itself to the output of your GPU - so if your GPU is only putting out 98fps, the monitor runs at 98hz (98 refreshes/sec), so there is never any tearing or stuttering or other issues.
What Aquorious was saying is that the GPU might not work with Freesync, as that is the AMD variant of Adaptive Sync (there are 3 - VESA Adaptive Sync, which is the base standard that almost no one uses, Freesync, championed by AMD and, as its name implies, free to implement, and G-sync, which is nVidia’s proprietary version that requires an actual hardware module in the monitor itself).
However, some time ago, nVidia implemented software support for Freesync in their driver, and while it is not “supported” - I.E. nVidia doesn’t guarantee it will work in all cases and wont provide you support - i have yet to encounter a a decent Freesync monitor that doens’t work with nVidia cards just fine, now.
The main issue you might have, is that Gsync-over-Freesync requires the use of DisplayPort cables, and im not sure if that GPU has 3 DP outs.
It should be largely academic, as you really only need Gsync/Freesync to be active on the display you’re gaming on. If it isn’t turned on on your secondary monitors, it wont hurt anything.
My personal opinion is that you’d probably enjoy going to 1440p more, and the 2070 SUPER is capable of 1440p and even 100+fps in a lot of cases (as its only slightly slower than a 1080Ti, which i have, and i drive 1440p/ultra/90-100+fps depending on the title, usually over 120fps).
Also, if you did a pair of 1440p monitors, you probably wouldnt need 3 monitors, since then your second monitor would be higher res and could fit more on the screen, you might not need 2 secondaries.
Up to you though.
1080p high refresh can be fine, too, that’s what my wife plays at (on an AOC FReesync panel with her 1080 ARMOR) since according to her she couldnt see a difference between 1440p and 1080p, YMMV).
Otherwise, the monitors you’ve selected look fine enough, and the two lower refresh displays will work fine without needing adaptive sync enabled.