I don't subscribe to the Lynette family twist theory, but the line between the emphasis on Lynette in the game and the emphasis on her in this thread is starting to blur, I'm getting confused you motherfuckers (term of endearment of course)!
I don't think the game has placed a huge amount of emphasis on her to the extent that we need a pay off. I think it's just that the MC is getting to know his "Family" (both the new [DIKs] and the old [his dad] as well as the new old [Lynette]).
But at the same time, if nothing much comes from the diary... It'll probably have more to do with sharing his past with his girls. He's already shared the mom's atrocious movie taste with Maya. Maybe he'll share his mom's love for anal with Jill (oh you
know Lynette was down with that!)