If this could be realised, that would be some impressive development. However, there are some other factors:

• Some of the above projects are rivals.
  
• Export potential should be limited by domestic consumption. Even moreso if the export possibility leads to rising domestic prices and with that a backlash, as is happening now:

Who's Winning The Natural Gas Game? - Domestic Critics Slow Potential LNG Export Boom - US Business News - CNBC

Heated debate over the impact of liquefied natural gas exports on domestic prices is threatening to derail them at a crucial time for the U.S. industry.

...Massachusetts Rep. Edward Markey, a top Democrat on the House Natural Resources Committee, is pulling out the stops to slow exports.

He began worrying about the impact of liquefied natural gas (LNG) exports on U.S. prices, when he saw permit applications piling up at the Department of Energy.

So, Markey and Sen. Ron Wyden, D-Ore., another key voice on U.S. energy policy, introduced bills requesting a timeout on LNG permit approvals until 2025.

...As a result, only one U.S. terminal has been given the go-ahead. A dozen-plus others are on hold, any regulatory action delayed until an Energy Department study on the economic impact is completed later this the year.

• For the effect on Japan, one also has to assume that Japan's current LNG suppliers will be able to maintain their export volumes until the US projects go on-line. (It's still rising though: Japan imported 78.5 million tonnes last year, that would be 10.5 bcfd on average; and this February it was 7.67 million tonnes or 12.9 bcfd.)
  
• US LNG export terminals seek permanent agreements with importing countries, so instead of summing up projects on the Atlantic coast, I searced for these planned agreements. There is Cove Point, MD (11 on map) for 2.3 million tonnes/year from 2017; Hackberry, LA (8 on map) for 8 million tonnes/year from 2016 [I omitted the link for this earlier]; Sabine Pass, LA (not on the map as it is the one already approved) with some portion of 5.5 million tonnes/year from 2015; and Lake Charles is mentioned in relation to Japan in news articles but with nothing specific. Further agreements are certainly possible, but I think imports on the basis of those would start at a later date.

_{*Lunatic*, n.
One whose delusions are out of fashion.}