Congratulations, Yellow Sign! You are the final player! The Druid idea is a good one, but it'll take some work to make it fairly playable in a mostly shipboard campaign...
As to other questions:
Xael:
I own all the Core Books, plus Masters of the Wild and Broadsides!. My collection, as you see, is fairly small, alas.
You can play a DMG Drow, so long as it's not a ranger who wields a pair of scimitars...

. Seriously, though, try to come up with a good backstory for a rationale for why a subterranean drow is on shipboard.
As for monk multiclassing, a monk can multiclass freely into any of the following classes: Rogue, Fighter, Ranger, Sorcerer, or Paladin. Wizard and Cleric require too much singleminded devotion to a craft alien to the monk, and Bard and Barbarian both require the character to be chaotic in alignment.
No, I'm not using Instant-Kill rules for now. I will see how it goes and then warn everyone if I think they are a good idea or not. But they are not being used for now, or the forseeable future.
Clobbering rules, on the other hand, will be used.
Levelling-up is done when the character has enough experience & free time. Each level up will need at least a few day's down time for training. Right now, I would say 4 days down time for levelling-up. However, like with Instant-Kill rules, we'll play a while, and then I'll consider whether or not I need to change the rules for levelling-up.
Good luck with the dice, Xael

I hope you don't mind my continuous "we'll play some and then see" approach to the rules, but that's sort of my style as DM.
Tonguez:
As to what the Seafaring domain is, it's a homebrew of mine, sort of like travel, but more ship-oriented than Teleport-oriented, if you know what I mean. Here it is for what your perusal:
Deities: Calypso
Granted Power: Profession: Pilot, Profession: Sailor, and Profession: Navigator are all class skills. Once per day, you may reroll any one skill check from one of the above three skills.
Seafaring Domain Spells
1 Starlight
2 Enhance Crew
3 Fathom
4 Mend Ship
5 Determine Location
6 Curse Voyage
7 Right Ship
8 Riverstream
9 Calypso's Blessing*
*Custom spell
Calypso's Blessing
Conjuration
Level: Clr 9
Components: V,S,M
Range: Touch
Target: one ship
Duration: Permanent
Saving Throw: None
Spell Resistance: No
When a priest or priestess of Calypso casts this spell, they imbue Calypso's blessing in one vessel permanently. This blessing has the following effects:
The ship's top speed increases by 4 knots
The ship's maneuverability class increases by one (thus maneuverability class E becomes maneuverability class D, for example)
The ship's captain and crew gain a +4 luck bonus to all Profession: Sailor, Profession: Pilot, and Profession: Navigator checks while on shipboard.
The Material component for the spell is a bottle of blessed seawater (holy water), which is poured over the bow of the ship when the blessing is given.
Your character concept sounds really cool, Tonguez. And thanks for the link, as well. If you have the stats finished, by all means, send them to me.
Btw, everyone, all the spells from the Seafaring domain are from Broadsides. If you do not have the book, I will send you the specifics on the spells and things that I have taken from the book.