No brainer....
#2...no back wall (the back wall in any proximity causes a lot of problems for a high fidelity listening experience)
side wall symmetry --> easily managed with pertinent predictable treatment at a future date (if wife permitted it).
1) speakers will be positioned such that it will only have 1 side wall. The other side will be open (dining area).
2) speakers will have both side walls (not equidistant) but no rear wall (my back will be towards the dining area).