No-one adds the 2 to Typhoon so I expect the 2 to drop off Lightning when it
gets to Marham.
I wouldn't count on it. The only reason there is no Typhoon 2 is because one (possibly two) of the partner nations has a very 'chequered' history with the Typhoon 1, and it was deemed expedient to drop the '2' out of tact.
Having said that, will be interesting to see how the Japanese take to the Lightning 2 moniker....(although I guess they can say they're following the English Electric name-lineage).