Kaiser answered the questions about Sheva Mitzvos well, if you learn the Rebbes Sichos about it, and see various Maanos, it’s clear the Rebbe never intended for people to waltz down the street accosting eino yehudim at random and shoving cards in their face, rather, as the Rebbe explicitly said, those who have day to day contact with non Jews in their environment, must try teach them about their 7 general Mitzvos. (There are far more than 7, seven are the general Mitzvos, but many more branch out of them. I’ll add Mekoros when I get a chance).
As far as Chabad Rabbonim and their opinions whether or not the Rebbe Zy”a will be Moshiach, I’d venture to say that majority aren’t convinced of that, but don’t necessarily make their opinions public. Rabbi Berel Levin wrote much about this, and he came to the conclusion that according to Rambam and the Rebbes own Sichos, the Rebbe cannot be Moshiach. Rabbi Immanuel Schochet A”H stated publicly that it’s highly unlikely for the Rebbe to be Moshiach. I have many other names at the tip of my fingers, but I hesitate to name people who are among the living if they haven’t publicly stated or written so.