I run a virtual centre and sit off centre without a problem. However, my speakers are work well at creating a good stereo spread with clear centre image. Why not try with yours and see how it sounds. The one thing that will kill the imaging in that room is if you push the speakers back in to the alcoves. An alterative might be, if your kit can cope (i.e. can you bi-amp the centre), to use two small speakers either side of the stove? I suspect that any speaker placed above, below or close to the sides of that stove will suffer fairly quickly.
For speaker switching wouldn't it be easier to use two inputs that have different channel allocations?