I recall that in LotR (and The Silmarillion), while it was not made so clear in the main series, the elves were actually categorized according to either those they chose to follow, or their geographic position (generally if they stayed in a place for a long time, it would be their location).
In DF, it seems that they are mainly categorised according to the elemental magic they have accrued. However, if cross-breeding (for want of a better phrase) occurred, they would probably categorise themselves as 'half-half' (if they even bothered to mention it). Or swamp the Hero with yet more unexplained etiquette and LORE, which could confuse the player, given that there are 8+7+6+5+4+3+2+1=36 different combinations, making a total of 44 different elf types.
Then again, it might make a fun puzzle for the die-hard forumites, while being unimportant to the actual quests. It'd be a lot of effort, though.
I wonder if there are any bacon elves...
If my theory about accruing elemental magic is true, the recently created Bacon element will not have any elves...
In any case, there are lots of people, be it Elf, Human, Fairy, Dragon or whatever else, who will happily throw their pride away if they're tempted with the right things.
But we have these things called moral fortitude and strength of character, that prevent us fromó
OMG is that a Cookie!? who do you want killed?