I would hang drapes from the outside and extend to cover the outlets on the sides. They don't have to cover the window just flank the sides. Best wishes!

Looks like no one has noticed the heat register on the floor !!! You cannot block it , hang curtains /sheer/blind on the inside and use a deflector to adjust the heat or cold flow . The corner windows should be treated as 1 , use a light weight fabric for your panels or omit and use blinds instead.

Outside like this

Jennifer Brouwer Design Inc. · More Info

Jennifer Brouwer Design Inc. · More Info

Definitely hang from the ceiling. It will make the room look taller, more spacious and more elegant.

"In my formal dinning I am planning to hang from the ceiling."

HAHAHA!

Your sofa will be centered with this window? Why hang drapes in the way of the sofa or heat register?

If you objective is a traditional visual, you could hang your rod at the top of the wall inside the niche; then choose window length curtains/drapes -- solid color drapery material -- and hang each panel over a window frame; and choose three sheers, one to hang over each window in between the darker curtain/drapery panels.