Hi Mike and Jen
For the big board, I think you'll be better off with the Kode 94 which is a livelier and more agile board. Big EVOs (relative the sailor weight) stay very loose and nice on the wave, but don't add much in terms of early planing when oversized. An EVO 90 would be easier to develop you (front side) wave riding on, but it sounds like you don't get much in terms of wave in this light winds.
For the smaller board, I think both will work. Your wife need not worry that the EVO 80 will feel to small. In many ways it feels just as big as the Kode 80 and the planing surface is pretty much as wide. The EVO 80 is, I would say, the liveliest and earliest planing EVO and I think that in this case it would work well for a 65kilo sailor. And for you, as you say, the EVO 80 will be easier in wave too and still feel nice in B&J too.
So I think your suggestion no 2 sounds like the best option.