(ともなう) Accompany, both literal and figurative: Bill accompanies Doug. But also, rain accompanies high winds at this time of year. (Notice how it doesn’t care about cause and effect.)
する(どうはん する) A person accompanies another person.
える(そえる) To come with, to be included with:(not used with people – in that case you’d say 伴)添える is more like, the CDR comes with the textbook. Or the applesauce comes with the pork chops.
(てんぷ) The noun form of 添える(そえる)。 (The file attached to your email.) (Read the attached instructions.)