Calling/Emailing Recruiters

I know there are many topics on this, but they offer conflicting, contradictory advice. Here's the situation: I have three potential interviews lined up, one at a MM IB, one at a boutique IB, another at a Big4 firm (management consulting, not Deloitte). Haven't heard back from any of them yet, but I'm confident I'll get at least 1 of them. I have the emails for all three recruiters, as well as their phone numbers. In terms of the specifics:

1. MM IB: The bank is doing on campus interviews next week. These interviews are held at a local target school (I go to a nontarget). I've met the recruiter, but our relationship is strictly professional. I have a few other contacts at the firm. Can I call and try to interview at the target? When is the latest I should wait to call? Should I call at all? Is email preferred? Considering all BB's and most MM's are far into interviews, this gets me worried...

2. Boutique IB: My contact isn't the recruiter, but a friend's friend who works at the bank. She was really helpful and awesome, until I asked to have my resume forwarded (weird how that works). She did it reluctantly it seems. Recruiting here goes from October - November. Should I wait it out?

3. Big4: Head of recruiting is a good friend of mine from high school. She's told me to expect a phone call and to be prepared. That was a week and a half ago. She's done a ton of work for me and I feel that I've emailed her enough as it is. Anyone know when Big4 consulting starts their interview process?

Sorry for the details, but I figure they were needed. Any help/advice on calling the recruiter back at any of these shops would be greatly appreciated. Thanks as always.