Not an FSJ owner, but in my JK I got a Scosche Magic Mount which is a magnetic phone holder. It comes with an adhesive plate that you stick to the back of your phone, I just stuck it on my phone's case, and the mount itself is adhesive as well. It is awesome though, holds up on and off road, bouncing around, the phone is held very well. Not sure about the cup holder idea, hopefully someone else can help out with that.
https://www.amazon.com/MAGDMB-MagicMount-Universal-Frustration-Packaging/dp/B00I608BJ8
You can get a similar device that has air vent prongs so you don’t have to worry about adhesive/sticky backing.
Here’s the option I use:
Maxboost Car Mount, [2 Pack] Universal Air Vent Magnetic Phone Car Mounts Holder for iPhone Xs Max XR X 8 7 Plus 6S 6 SE, Galaxy S9 S8 S7 Edge, LG G6, https://www.amazon.com/dp/B01M0GTZDN/ref=cm_sw_r_cp_apip_U9z1HV8vhLIPq
Maybe something like this would help the air quality in the Jeep? https://www.amazon.com/Philips-GoPure-Compact-Purifier-Pack/dp/B00P2D46VE