While I think this is a good idea in principle, most of these slogans don't seem very effective because they suffer from the illusion of transparency. Consider what they must look like to someone viewing this from the outside:
"AI must be friendly" just sounds weird to someone who isn't used to the lingo of calling AI 'friendly'. I can't think of an alternative slogan for this, but there must be a better way to phrase that.
"Ebola must die!" sounds great. It references a concrete risk that people understand and calls for its destruction. I could get behind that.
But I'm afraid that all the other points just sound like something a doomsday cult would say. I know that there is solid evidence behind this, but the people you are trying to convince don't have that knowledge. If I was unaware of the issues and just saw a few of these banners without knowing the context, I would not be surprised to find "Repent! The end is nigh!" somewhere nearby.
I would recommend that you think of some more slogans like the Ebola one: Mention a concrete risk that is understandable to the public and does not sound far-fetched to the uninformed.
Existential risks are the risks of human extinction. A global catastrophe will happen most likely because of the new technologies such as biotech, nanotech, and AI, along with several other risks: runaway global warming, and nuclear war. Sir Martin Rees estimates these risks to have a fifty percent probability in the 21st century.
We must raise the awareness of impending doom and make the first ever street action against the possibility of human extinction. Our efforts could help to prevent these global catastrophes from taking place. I suggest we meet in Union square, San Francisco, September 27, 2014 at 2:00 PM in order to make a short and intense photo session with the following slogans:
Stop Existential Risks!
No Human Extinction!
AI must be Friendly!
No Doomsday Weapons!
Ebola must die!
Prevent Global Catastrophe!
These slogans will be printed in advance, but more banners are welcome. I have previous experience with organizing actions for immortality and funding of life extension near Googleplex, the White house in DC, and Burning Man, and I know this street action, taking place on September 27th, is both legal and a fun way to express our points of view.
Organized by Alexey Turchin and Longevity Party.
Update: Photos from the action.