Hm. I’m not sure. This link here says you can also use the home button, if you have that (https://support.mozilla.org/en-US/kb/playing-videos-firefox-android#w_picture-in-picture-mode).
You might also have to allow Firefox to have PIP view in your phone’s app settings (Settings > Apps > Special app access > Picture in picture).
Not sure if this is universal, since I don’t think I have any add-ons. But I open the video, put it in full screen, and then swipe up quickly from the very bottom bar of my phone and it goes into PIP view.
My cat doesn’t care for people food, but she does paw at my arm until she gets to smell my breath when I’m eating. Our routine is for me to take a bite, open my mouth and breathe at her, and then she sniffs and walks away.
No. The article says she passed away in June 2011.