Fordan
Contributor
As others have said, most training agencies have 4 scuba dives split over 2 days once you've completed your classroom and pool work.
As for how far south, what's your tolerance for cold? Getting used to some cold might not be a bad thing if you want to dive near home... Most people can do only a couple of dive vacations a year, but if you dive locally, you can easily dive when you have free time.
Assuming you're looking for warmer waters, I'd probably let airfare shopping pick the destination. Look at Florida, and various locations around the Caribbean/Mexico, and see what's cheap. Cozumel/Cancun, Cayman Islands, Virgin Islands, Bahamas... Most areas around the Caribbean Sea have pretty decent scuba setups, at least the ones with reefs.
Assuming your company is talking from a PADI perspective, yes, you want Open Water IMHO. I will warn you that there are other terms for the same type of certification, such as NAUI's "Scuba Diver" which is their equivalent to Open Water, so when comparing different dive shops to get the training, keep that in mind. Even if who you dive with in Australia has the spare dive professionals to send with you, other places you go in the future may not, so having the training to dive without a chaperone is a good thing.
For most dive locations, including the liveaboard I did in Cairns, generally you'll get about a 5-10 minute briefing on the dive site: it's structure and layout, the sea life you're likely to see, and any max depth/time/tank pressure limits the boat wants you to follow. After that, you and your buddy (if you don't have a pre-arranged buddy, you'll get paired up with an "instabuddy" who's in the same boat, so to speak) hop in the water and dive. The dive op may send a divemaster into the water to conduct a tour, but not everyone does that, and many/most people will go off on their own in buddy pairs anyways. There are many variations on this, like Cozumel where the local rules require 1 divemaster in the water for every 6-8 divers, or Bonaire, where much of the diving is shore diving on your own, so no dive professional and no briefing for those dives.
Your choice of dive agency isn't a huge deal once certified. Everyone honors everyone else's C-card and treats them as equivalent. I did my basic training with NAUI and got a Scuba Diver card, followed by doing Advanced Open Water from PADI, Rescue from PADI, and am working on Master Scuba Diver from NAUI. The two agencies treated each other's cards as meeting the prerequisites for the new training, and I believe that's true for most agencies. The only place choice of agency might trip you up is doing the referral dives you're planning, and I don't think it will. If I understand correctly (not a dive professional; someone who is please correct me), PADI only allows referral dives to other PADI shops, whereas most others have universal referral systems where instructors from many agencies, including PADI, can sign off on your dives. This isn't a huge issue since PADI has a major presence worldwide, especially in the resort areas, so where you go for your referral will likely be PADI.
I'd probably talk to the shops in your area, see who can meet your schedule and who you get a good feeling from (interested in discovering and meeting your needs, doesn't look at you with $$$ in their eyes, etc), then ask about referral issues. Many people post here looking for what the best agency is, and over and over the best advice is to find a good shop and instructor, and not worry about the agency.
