The bold I wouldn't bother bringing personally. They have a medicine kit if you happen to need some allergy pills or tylenol etc. You have lighting in your rack and the cabins so no flashlight should be needed on-board. Personally, I spent my time with the other people on-board and was asleep quickly after my head it the pillow, so I had no need to entertain myself with books or magazines. Tools, as mentioned, they have onboard as well. Temps in march should be low 70's to mid 80's during the day and probably mid 60's at night. If you need a knit cap for 65F weather, then bring one, but most people are pretty comfortable at those temps in my experience.
I used 2 swimsuits, 1 I was wearing and one hung up. Additionally, I found 2 towels best if you plan on showering. Keep one on the hook by your rack for shower use and the other topside for drying off after dives. They had tons of clips for hanging your stuff topside, but I still preferred to use my own so bring them if you'd like, but you could probably get by without them (most of the divers with me just used what was there already).
A 5mm suit, unless you get cold easily, would likely be overkill for most of the dives, but the night dives feel much colder so it's probably a good idea to have an option to get warmer than a 3mm will get you (I used a 3mm for all of my dives in December, one of the women onboard used a 7mm with hood for all of them, and another guy never bothered with a wetsuit at all.. so it is highly dependent on how you tolerate the cold).
You can tip with a CC (I did) and it is processed through the US. The sale of shirts/hats/etc wasn't an "anytime" thing when I went, they set up the "ship's store" for that on the trip back to port after our last dive of the trip.
No SMB is needed as mentioned already. You only have one drift dive and we had crew out with us in the water (ahead and behind the group) plus the dingy plus the boat.
I was just there in December so it's still pretty fresh in my mind. Let me know if you have any other questions.
