2. The BL 11 is possible, via direct Line with an RCA cable to Power Link to equipment that is not B&O.
3. The same Power Link cable used by a BL2 can be used with a BL 11.
4. In two rooms 5x5; With a BL11 you would place another pair of BL3 fronts and on the other with BL2 a pair of BL 4. (both BL3 and BL4 use the Power Link 2)
5. A Cube 2 Focal SW sounds good to you, in a 5.1 accompanied by 4BL front and rear; or you would put 2BL 3 ahead.