unofficial doctrines: baptismal rites

having to wear white.
hair and/or dress can't float up.
exact word for word reptition.

that's all that i can think of off the top of my head right now. are these things absolutely necessary for baptisms, or are they things we do by tradition and symbolism? if it is necessary, does that mean that if the witnesses miss one of the above, that the baptized person's rite was insufficient and invalid?

what about the word-for-word repetition? i know christ said to say those words in third nephi and that oliver cowdery used third nephi for the basis of d&c 20, but did jesus mean it 'word-for-word'? also, jesus wasn't saying those words recorded in the book of mormon, that's just joseph smith's translation of what he said. and then what about missionaries in foreign countries. who decided which translation is the proper word-for-word usage for baptism?