Hey Travis,
I take it you're doing Ironman Korea? Haven't done that race, although I have been to Korea a couple times :-) I'll assume that's the case, so pardon me if you're talking about another race.
Anyway, found some info under the "Rules" link from the Ironman Korea race website that might help you. http://www.ironmankorea.net/eng/event/rule.jsp
This is what they say about your bike special needs bag:
Bags will be provided for the Special Foods Station located near mid-point on bike course. Special Foods Station is for nutritional purposes ONLY, and ONLY food items will be allowed in the bag. All unclaimed bags will be DISCARDED after station is closed. Athletes will be required to slow or stop in order to retrieve special needs bags.
Sounds like they only want you to put food in there, although here in the US you can put pretty much whatever you want in there...whatever you think you might need about half way through the bike that you don't want to carry with you. Notice though, you won't get the bag back after the race, so don't put anything in there you want back.
Pretty much the same verbage about your run special needs:
Bags will be provided for the Special Foods Station located near mid-point on run course. Special Foods Station is for nutritional purposes ONLY. All unclaimed bags will be discarded after Special Foods Station is closed.
It would probably be a good idea to read through the rest of the rules, too. Might help you answer some more questions and avoid some confusion come race day.
They will probably provide portable toilets for you at every aid station. I see the locations of the aid stations are indicated on the bike and run course maps:
http://www.ironmankorea.net/eng/event/index.jsp
Around here, technically public urination is illegal. BUT, the reality of races like this is that sometimes it might be necessary. What they tend to say at Ironmans here is basically, "if you must go, please do so discretely." In other words, please don't pee in someone's front yard while their kids are outside playing. You would know better than I if the "code of conduct" for such things is different in Korea.
Good luck!
-Steve