COOL makes too many happy couples for this to go south, plus Elma's the only dragon without a love interest so i can really see this turning out to be good after a little turbulence
Female on female wouldn't realy be odd, dragons being natural shapeshifters, they can have or give someone a working penis if they wanted and call it a day.
So either Kobayashi or Tohru still works.
Kobayashi have sword boy with God level anyways. The decision is hers, not impossible to fight, just how to find a best way to resolve this. I hate arranged marriages, specially political marriages, feel like selling your own daughter/son for money or relationship between 2 rich families