I personally think this is a good idea, but at the current time. VR costs way too much to sell to your average Facebook user, not only that. You need at least a half decent computer which ain't cheap either. Most people don't use a computer for Facebook, most use their mobile phone or tablet...
That is still aloud. It's not breaking any rules ofc. He only states that because then it would be easier for the Development team to read than scrolling through more than 1 thread.
Create 2 voids. One being to set their colour name and one to set it back to default.
Call the Colourname before they send the message, then after call the DefaultName void you made.
They're most likely just going to wait and see how much it effects them, if it effects them too much then they will start to consider moving to HMTL5. Personally I don't see them switching, nor do I think it will effect them too much.