G2's start date is 1997, officially.
Mind you, it always bothers me how G1 has become 1983, when it should be 1982. It doesn't matter if the first full launch year was 1983, the hoof stamps are 1982, which means the designs were finalised. And the first ones snuck out around December 1982, according to reports.
Based on that, I would expect them to go with 1998 for G2 (if they recognised G2). Because that was when they were around globally, although I remember them being discussed when I first came online in 1997. I am sure DV had them mentioned on the site. So that would make next year 25 for them?
Light Heart and SunnyDaze have similar colour schemes...Sunsparkle and Pinkie Pie kind of do but not as much. But the obvious should really be Applejack, Applejack and Bright Bramley IMO.