The three businessmen are interesting to me, but not necessarily suspicious. They're all dressed the same, which would lead me to suggest they are connected in some way. Furthermore, they already know each other before this all went down. I wouldn't put it past Squee to make a third killer, but I don't think she would tie them together like this. 

What is it that people find so suspicious? Their attire? The "weighing the pros and cons" bit?

I'm not so sure that suits mean much of anything right now. And who wouldn't discuss whether or not they should leave the bus?

Maybe I'm glossing over something important, but it strikes me odd that Squee would be so obvious in her first post.

I know from my own experience that it is much easier (and more fun) to have the killers be background characters in the first post.