Do the related browser.gesture prefs on the about:config page still have a value set for those gestures?

Which Firefox function should be performed with those gestures?

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.

It looks as if they are all set to the defaults

Are the still functions assigned to the pref for the gestures that do not work for you?

Some gestures have been changed and now have an empty string, so they do not have any effect.

Here is a screen shot of the about:config file.

You can see on the about:config page in your screenshot that the browser.gesture.pinch.* and browser.gesture.twist prefs do not have a value set. So they do not have any effect.

Which function do you want the browser.gesture.pinch gesture to perform?

I use the trackpad feature to resize the screen, both larger and smaller as needed. So that is what I like it to do. It works on all other apps except version 4 of Firefox.

Oh...and thanks for helping with this.

This is broken in 5.0.1 on Mac for sure. Poor planning and programming I'd wager. Or incomplete testing.