I don't think you'd catch an educated American using 'nite' and 'color' isn't dodgy, but a legitimate American variation which was decreed by Noah Webster, but wouldn't have shocked a C15th Briton.
I don't want to adopt US spellings either, but I don't buy the idea that Americans have taken 'our' language and spoiled it.
Hallowe'en is elegant, but is just an apostrophe too far, now we don't use 'even' for 'evening'.