You're only slight challenge will be the angled wall between them. I would start by looking at this window as though it was 2/3 of a bay window. The photos below are of bay window treatments. Two valances side by side will work fine........they can meet in the corner. An angled cornice with or without panels. If going with a soft valance with swag sections and side jabots, you could have a single swag over each window and jabot on each outer sides. I try to think of window treatments as "a la carte". Take what you like from several and combine them into what fits you.

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