...my very 1st liveabaord was on JULIET/Bahamas in Aug 2004 and I had a GREAT time! The boat only holds 12 passengers max....we dove in a 'big' group....I just hung with the group on some dives....and I even had my very own private DM on a number of dives (a cute young female Brazilian marine biologist). Some divers did their own thing...others went with the DM.....I ended up with my own DM sometimes just by chance......she wanted to go diving but not everyone wanted to use a DM on every dive so sometimes divers paired off or into their own small groups to do their own thing and in those cases I was more than happy to have my own cute/free/private DM!
I wasn't quite as much a 'newbie' as you appear to be, although I was still fairly new to blue water diving, only having done Coz a few times prior to the JULIET trip. Honestly, I found the JULIET/Bahamas trip to be a very gentle one, quite suitable for a new diver, and you will likely gain a lot of experience in a very short time. The boat provides/offers DM lead dives, so do the smart thing and take advantage of it.......the crew members will be different as again, I went 5 years ago......and although sometimes the boat crew/DM's can suffer a level of burnout/boredom sometimes........sometimes the crew will still be excited and glad to go diving with SOMEONE...ANYONE.......the group....you.......whoever......remember, if they're not out diving with you, they're stuck on the boat scrubbing toilets, etc. ! ....so give the DM's something to do besides boat chores!
JULIET is not the super high intensity liveaboard......many liveaboards offer up to 5 dives daily...or have an 'open pool' policy telling the boat deck is open from 8 AM to 5 PM and you can do as many dives as you want, whenever you want......JULIET was more a 4 or 3 dives daily routine.....but no biggie, being a new diver you'll already be plenty busy so relax and enjoy. Go ahead and get NITROX certified....you'll thank me, NITROX is God's gift to repetitive divers! Max depth and currents....who knows, weather / currents depend on so many variables....and on my 2 Bahamas liveaboard trips currents varied from zero to mild to significant......depths, well, if you do wall dives the depths are as deep as you're brave enough to go ( without violating NITROX MOD's/deco/gas limits )...the boat will give you dive briefings, including max depths at the sites, as well as any boat imposed depth -safety- limits, if they apply.) On JULIET, it was rare to exceed 100', most dives were in the 40' - 60 ' - 80,90' range. Tell the crew you're new, they'll take care of you....as long as you're not special-ed and have a handle on your weighting/bouyancy control and are monitoring your depths/deco/gas limits you'll be OK. The boat isn't going to drop you into a dangerous current situation...but do bring basic safety gear (safety sausage) in case you somehow get separated. Don't know how your air consumption is, the boat only offers AL80's (and AL63's) so you won't be able to get ahold of 'big' tanks....but you can make a special request of the crew to make sure your tank is fully topped off with no short fills....from what I remember they were pretty good about giving 'full' fills. I have no idea when you are doing this trip, but bring enought thermal protection.....new divers pretty much always underestimate their thermal protection requirements, especially on a liveaboard when you're in the water 4, 5 or even 6 hrs daily. Although you will likely have a different cook than I had....our cook was absolutely amazing...I have no idea how he managed to do it, especially when you see how small the kitchen area is!
....just remembered, the boat offered 17 dives over 4 1/2 days....I only did 15 dives as the boat cancelled the final morning's 2 dives to give us a 12 hr head start to 'run' from hurricane 'Charlie' and get to Miami in time to evacuate before the airport got cpmpletely swamped (that was the yr 4 hurricanes hit Florida in a 6 week period...'Charlie' was the 1st of the 4 hurricanes.)