Too late. They most likely missed the crypto train. Banning crypto ads and accounts damaged their reputation and it wasn't already in a good shape before it.
It will still create some hype however. It still has a name which is worth millions of dollars. Just a name...
Believe buddy, when i say this, what you mentioned above won't in anyway do any harm to facebook doing an ICO. In fact, it will instead increase the popularity of facebook all around places over the world.
I don't get this facebook popularity will increase even more if it will conduct an ICO. It's as if cryptocurrency investors are not yet aware of facebook. If anything, it's cryptocurrency whose popularity might increase because of this move by facebook.