That example where you used square video and put the text underneath is awesome. This technique helped move people from horizontal to square on Facebook this year. I think we’re slowly we are moving to more vertical content oriented world. When you talked about the different sizes on Facebook not displaying properly, I believe it’s because it changes it to a 1080 x 1350 viewing experience. I’ve had this trouble uploading vertical vlogs to Instagram since they cut off a lot and learned the hard way :P. They talk about it in their recommended size to upload: https://www.facebook.com/help/instagram/1631821640426723
Great write up!