The increased drag will probably be directly related to the increased AoA.
Increased AoA = increased downwash = increased drag.
Add to that, that the underside of the wing, even with the displacement of the leading edge (by increasing the AoA) will most likely be less effective in the lift departemnt than upright, you again need to increased the AoA to get the same amount of lift out of it, again increasing the drag.
Parasite drag could also be increased, as the leading edge is now more blunt than in upright, although this would depend on the design of the airfoil.
How much the angle of incidence would affect it, I guess it's more relevant in the stall department. (Outer wing would stall first).
Dihedral will definitly affect stability, but I dont know if there's other effects

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I'm no aeronautical engineer, just a PPL with a keen interest in aerobatics.
Daff
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CO, 56th Fighter Group"This is Yardstick. Follow me"