Would putting a poached egg on top of pan fried duck with orange sauce work (served with egg noodles)?

Sure...why not? I ask myself "do I like these flavors?" and "are the flavors somewhat complimentary?"...and if the answer is yes, I go for it. Rules be damned! ;)

I would just consider adding something acidic and something fresh to counteract the fatty-sweetness going on. Scallion greens and a touch of rice vinegar?

MMMMMM I would put that bad-boy poached egg right on top of the egg noodles and mix in all that yolky goodness!

I say go for it, but duck is so rich that I don't know that you would need the richness from an egg yolk which would be all that the poached egg would contribute. Try it and let us know how it turned out.