Here is a review about TAP Business Class from just 5 days ago:
https://thepointsguy.com/reviews/tap-portugal-new-a330-biz-review/
I looked at Paris - NYC on Norwegian and they are taking bookings on that route through October 19, 2019. If there are no flights showing up after January they may be dropping that route. Which they do often. I flew BOS - LGW in their Premium Class in May. It was OK. It wasn't really what I would call business class, though. Food was not good. No pillow, which you need as there's no back support on the seats. And when the person in front of you leans back you are pretty much stuck in your seat. Window folks have no way out! If I flew them again I would wait until maybe 6 weeks out, bring my own pillow and my own food AND water. We got one bottle of water and that was it. The movie selection was good though and the Dreamliner is a nice plane as far as air quality/comfort goes.
Norwegian has stopped flights out of Hartford and a couple of flights to/from Edinburgh and Belfast this year. The routing you want might be seasonal - could you move PAST January to see if they may start again in May or June?
Does
DCL book one way flights for people on their cruises?