All of which have the same issue. A sms:// domain still needs the user to install it. A prompt to install software will very much tell you what that software wants to access and to do and apps that reach data or functionality of your phone that is sensitive (at least in FxOS) need to be hosted on the marketplace and get a security review. Normal web sites are not allowed to access everything https://hacks.mozilla.org/2013/11/firefox-os-security-part-1-the-web-security-model/ .
I very much agree that vibration allows you to get the user’s attention much better than without it, but I am not sure about the credibility aspect of it. In essence this is like a fake browser toolbar and a ping sound – or a desktop notification like Chrome has with a ping sound.

My fave fake interface lately was this: https://www.youtube.com/watch?v=3SKDbmQosfg