1. Is it possible for 2 out of 3 display ports to have the same issue, but the 3rd be fine?
Yes, but this is usually very rare. With the GPU connected via one of the DP ports, go to your Viewsonic monitor's onscreen display and check that the DP connection is set to 1.2 or Freesync. These need to be enabled on the monitor in order for Freesync to work over DP. The HDMI port of the monitor may or may not support Freesync. You can tell if it does by connecting the monitor to the GPU via the HDMI cable and going to Radeon Settings -> Display
2. Is having louder fans upon reboot a normal occurrence when updating graphic drivers?
This is normal for custom cooled cards that run in semi-passive cooling modes (fans not spinning when idle)
3. I've contacted XFX and have not heard back from them yet, but should I wait to hear from them or do a card swap at my local Best Buy?
If the issue still happens after checking the above steps, I recommending swapping the card at Best Buy for another one before the return/exchange period from Best Buy ends. However, I don't know how recently you bought the RX 580 since the return/exchange period with them is usually 15 days from the date of purchase.
First off, thank you so much for the reply, I really appreciate it!
1. I've confirmed the 1.2 and Freesync options on the monitor are both checked while I testing. Currently on the working port, both are checked and it works fine. I've also confirmed that this monitor does not support Freesync over HDMI due to the option being "Not Supported" under the Radeon Display settings when using HDMI. I think this may be one of those rare cases then sadly.
2. Thanks for the answer, I'm going to assume that portion is fine then.
3. Currently I'm looking to do the swap at Best Buy, I've bought it within the past 45 days which is my return window with them.
I DID end up calling XFX though and they wanted me to try a different cable, but due to my testing I really don't think it can be the cable because cables usually don't pick/choose which ports to work in. I think that I can rule out my monitor/cable because of all that. My last test before I go swap will be hooking up the second monitor via the DP adapter on the bad ports again to confirm the mouse stutter I mentioned in my previous post. If the stutter doesn't happen on my good port, I think it'll be safe to assume it's the two ports causing the issue.
Again, I appreciate the response. I feel better hearing other opinions.
So I ended up swapping out my card at Best Buy and all issues were resolved!