I would say you're both correct. Its known that their new 321neo aircraft aren't off the production line yet, hence why they've had to cancel flights.
Any company regardless of the industry will cut ops which have the least economic affect on its finance books. So we can assume that STN sales have been better than BHX. I'm not surprised that BOS was suspended as it's a new market for BHX and would take some time to develop, it does not mean it will wont be successful in the future.
Primera at the end of the day are leading the future of transatlantic travel, narrow body long haul flights will be extremely common in the future of aviation (even IAG have ordered the 321LR) and generally they will even have lower cost base than Norwegian LH from LGW because of the aircraft type and lower fees at STN.
Regarding shoreline check-in, I don't think Emirates will use it as the belts wont be in place in time and they apparently require more than 8 desks. I imagine they will use Zone B as it's not used in the evening.
Not sure if this has been mentioned here but MV ATH has been suspended indefinitely, CO LCA are reducing their schedule to two flights a week in S18, I imagine because of their new LHR flights. Finally IZ TLV are returning will a full schedule between April to October.