I'd warn you not to overlook the certification factor. Changing the configuration layout of an aircraft requires a new LOPA to be produced and cleared with the airworthiness authority. If you are reducing the number of seats, don't move any bulkheads and leave interwiring alone this is usually no problem. If you move a class divider bulkhead by so much as an inch or put a seat where none has gone before, then you may need to redo the load interface data through the aircraft constructor (exact deatils depend upon the local regulatory body.) Can the cabin crew see every passenger location from their seats? Can you prove it? Changing the IFE or PSS wiring? Oh dear! Do take care...
We do lots of reconfigurations on our own aircraft but we have a pile of previously certified LOPAs on file to work from, and contingency spares ready in stock. Doing a change thus takes about 10 hours. Reckon on three days working from scratch and check the regulatory requirements and issues with your local regulator well in advance.
**********************************
THrough difficulties to the cinema