Could drag in a turn be twice the drag of that encountered in straight and level flight?
Could drag in a turn be twice the drag in straight and level flight?

Yes, but this will be a rater steep turn.

…  in a coordinated turn with the same angle of attack at the same airspeed …

No, this is impossible. Either angle of attack or speed have to be higher so the higher lift required for turning can be generated.

… angle of attack is the same, the lift to drag ratio is the same. In this scenario the load factor is 2

And in order to create twice the lift of straight flight, the speed has to be higher by a factor of √2. In this case, L/D is indeed the same, but speed is higher so twice the dynamic pressure is available for creating the required lift. Since both lift and drag are proportional to dynamic pressure, creating twice the lift at the same L/D means that also drag will double.
In order to turn with a load factor of 2g, the bank angle has to be 60°. That is rather steep.