I recently pitched a bunch, so I've got some wisdom to share!
1: Two weeks is pretty much fine. Generally I've heard that unless you heard back within a week, they're unlikely to be interested. Publishers get loads of emails every day and they don't have time to reply to each one. After a month they'll have long forgotten about your email.
2: All of them at once is fine, really. Nobody bats an eye at that. Negotiating publishing deals often takes months, during which there's plenty of opportunities to notify the publisher that your in talks with other people as well. When I spoke to a recruiter, he just asked me if I'd contacted anyone else, and recommended that I do in order to increase me chances of getting a publishing deal.
Overall, pitching to indie publishers is a lot less formal than you'd imagine. They're all there to do business, of course, but everything is pretty friendly and laid back in general.