In regards to the Dyad thing, once again, merits on both sides of it.
I think I lean towards them “always being a dyad” is it really helps explains stuff in TFA as Jar Jar brought up right now, but also for me specifically, how Rey was able to, erm, “download” Kylo’s powers and abilities without doing a dang thing. So for that alone, I’m ok with it being something they always were.