1) Tip what you feel comfortable with. Don't tip at all if you don't feel comfortable doing so, or feel free to tip exceedingly well if the guide works their my friend off. What do I mean by that? I mean this: Does your guide sit in the drivers seat all day and look at his/her watch? Or do they interact with you, check your gear regularly, explain why they're doing what they're doing, etc? Remember, it's not really based just on how many fish you do or don't catch.
2) Yes, most decent saltwater guiding outfits will have boats with a "head" (boat-speak for a toilet).
3) If by "local" you mean the Vancouver area, I can't say enough good stuff about Bon Chovy and/or Pacific Angler. Great folks that run tight ships (pun intended). Don't expect any halibut fishing around here though - it essentially doesn't exist.
Good luck!
*edit - really? the 3 letter version of butt ending in "ss" is edited to "my friend"?!? lol