Yes, this 1791 Gunleather ORPDH24SSBLR BH2.4S Optic Ready Black Leather OWB Holster will be compatible with an FNX-45 Tactical. Your slide and barrel will poke out from the bottom of the holster, but it will still fit.
The 1791 Gunleather BH2.4S Optic Ready Holster is not compatible with the P220 Elite. I would recommend the Comp-Tac International Outside The Waistband Holster, found by using the link below:
https://www.opticsplanet.com/comp-tac-international-outside-the-waistband-holster.html?_iv_gun-model=sig-sauer-p220-1
This 1791 Gunleather BH2.4S Holster is not compatible with the Glock 43X. I would recommend the Black Scorpion Outdoor Gear Glock OWB Kydex Paddle Holster, found by using the link below:
https://www.opticsplanet.com/black-scorpion-outdoor-gear-glock-owb-kydex-paddle-holster.html?_iv_availability=in-stock&_iv_code=BSO-HT6-GLKPH-HC03-PADDLE-GL43XBKLH
Possible but not guaranteed since this holster is not labeled as optic ready.