I can also confirm that, after the last update, FoxFi works fine on a Verizon S5 with unlimited data. As another user mentioned, you will be forced to set a password or pin lock screen (it won't let you use fingerprint pattern) the first time you use it. If you don't already use a lock screen, this can be kinda annoying. The only way to remove the lock screen is to clear credentials (Settings -> Security -> Clear Credentials). I don't use Foxfi that often, and I don't use a lock screen, so i just clear the credentials after each use and the lock screen is disabled. Not too much of a hassle for "free" tethering.
Also, if you're having a moral dilemma about doing something that Big Red doesn't condone, you can enable/disable wireless hotspot as needed using the My Verizon Mobile app and you will only be charged the pro-rated amount for the time you have it active. For example, I was travelling for 4 days last month before the Foxfi update, so i enabled hotspot for those four days only. No impact on my unlimited data plan and I was only charged $4 for my usage.