Interesting outline for a story, but it doesn't really strike me as a drabble.  I think it would make for a great story, but as is, it seems too narrirated to me.

I just love happy endings. This felt more like a summary than a drabble, though I really enjoyed it. Also, a small formality: Lord and Lady are subjects of the Royal house, so a prince would be "higher ranking" than a Lord or Lady, though noble they may be.

AWWW! I love happy endings.  I hope Kikyou and Naraku got everything they deserved.  I am sorry Sango, Miroku, and Inuyasha had to die but I liked the one shot very much.  It also leaves room in case you decide to expand and do a series of one shots on their future pups and how they handle things after the demise of Naraku.  Also I would love to know how Kikou became his mate. Great one shot.

Wow, this drabble left me wanting more! This would make a great story if you chose to expand it. Well done!