Lilly:
I can see an end CG with ALL 3 elements with her. Hisao's married to her and we see Lilly pregnant, already with a couple of little ones in her arms. Bonus points if the devs show Hanako in the background holding/playing with one of Lilly's children.

Hanako:
I've seen the fan pics of Hanako's parents holding a baby Hanako up, and I think a great end CG for her is a photo of Hisao and a very happy Hanako holding up their first child together. A CG of Hanako in a wedding dress would be cool too.
Emi:
I'd say a wedding scene with Emi, plus a CG of a pregnant Emi, just to satisfy the pregnant loli fetishists out there.

Rin:
I can't really see Rin in any of the above themes, but that awesome proposal pic by Doomfest would be great for an end CG. Hisao, stammering out his proposal, and Rin, staring at him blankly for several seconds, then blurting out suddenly, "Sure, why not? It'll be fun."
Shizune:
I'd imagine a CG of a mini-Shizune running around with the same personality as his/her mom, giving Hisao a heart attack with his/her antics.
Misha:
Even if she doesn't have her own path, she could still show up in an end CG (most likely Shizune's). I'd imagine she'd also be married and have twins, a boy and a girl, just as loud as their mother, with the end sequence of all 3 of them laughing in unison at Hisao...oh the horror!