If Norwegian are involved then double daily will be to SWF not JFK the numbers on a narrow body don't add up for JFK across the Atlantic, I have also heard mention of LGW to SWF, I know one of the directors of stagecoach who operate the shuttle between SWF and Manhaatan and he had been told that there would be multiple new routes out of SWF to be announced within days by Norwegian on the max.
It's also telling that Norwegian have yet to publish a summer program from LGW to the costas, Monarch as a brand operated by Norwegian might bring better returns.