Is there any Forgotten Realms lore (3e/3.5e era preferred, but 2e sources could work as well) that describes or shows the basic flow of an Elven bonding (marriage) rite, or provides clues as to what such a rite would consist of? I have been pointed at a couple of homebrew sources, but they are basically adapted forms of typical RL Western rites with no citations to official material, so if there is lore out there, I would rather see it before I go off and make another riff on typical RL Western rites, and if there isn't, I would like to hear from someone who's RPed this sort of thing before (perhaps there are other RL traditions that are more thematically appropriate as a basis here).
Races of the Wild gives a starting point
Pages 5 through 36 cover Elven culture extensively, including comments on family, marriage, and children.
This material can only serve as a starting point, however as it is a 3rd edition book, and thus defaults to Greyhawk, in the world of Oerth, rather than the Forgotten Realms.
Nonetheless, it is a good reference on D&D Elven culture in general, due to cross-cultural influences from various settings (Spelljammer, Planescape, and the default assumption of inter-Prime accessibility between Greyhawk, the Forgotten Realms, and our own Earth) which is built into the 3.x edition of the game.
They gloss over details of the marriage rites, probably keeping it vague on purpose in order to allow for DM creativity.