Alright then, I figure I might as well start detailing the three incomplete characters.
First up, we have Lifen. We were originally going to give her a "stupid" name ala how Taro wanted to be called "Awesome Taro" in the manga (he never says what he wants to be called in the anime), but communication kind of... broke down. Anyway, in terms of physical appearance & personality, Jupiah came up with this suggestion:
A hyper, athletic tomboy, with short spikey blond hair and blue eyes. She's arrogant, conceited, short-tempered, agressive and talks down to those around her. She thinks of herself as cool and mature, and heaven help anyone who disagrees. However, she can be actually be fairly nice to those who don't insult her or challenge her authority. Sort of like Asuka Soryu Langely, except even more arrogant, not quite as violent and much more mentally stable.
My own comments was that, from the start, I envisaged her a dominant/domineering type personality. She dislikes Yemon and makes no bones about it, a rivalry that started early in their lives. One vague idea was that part of the rivalry stems from the fact he's a natural leader, while she has to bully and browbeat others into obedience. Despite this dislike, Lifen is also conflicted as, deep down, a part of herself that she denies has a crush on Ranma's firstborn.
We decided eventually that Taro decided to "improve" his daughter shortly after her birth by giving her a Jusenkyo curse- and not just any curse, but a very powerful one. He ended up hooking up with a wizard, who promised to make him a unique batch of water for his daughter. He did so... but he cheated Taro (either deliberately or for some other reason, we never decided); rather than simply being naturally powerful like Taro, Lifen has to actually train her curse-form to acquire it's powers. We contemplated making the wizard into something of Taro's nemesis; Taro is always trying to get revenge, but he always manages to evade trouble, often slipping Taro a dodgy magic item or spell in the process.
Lifen's exact curse is as yet undecided: it was when we were trying to figure out what it could be that Jupiah vanished. Seeing as how I have a preordered copy of the 3 main books for D&D 4th edition, including the Monster Manual, does anyone object to my offer to examine the MM and see if there's a suitable form there?
Jupiah suggested some things for Taro's wife, which I'll repeat below along with my own responses, but I think we'll need to figure out just how Taro met Ranma & the Chinese Amazons and how he ended up getting mixed up with them; Ranma left before Happosai woke up, so while Taro might have a fight with Ranma & Shampoo before going to Nerima, he's got no real need to challenge them to a rematch after he fights Happosai. Jupiah suggested that Happosai might send him to take on Ranma as "revenge" for Cologne taking him, but how would Happosai find out about Ranma in the first place?
I would write him as actually living in Joketsuzoku with an Amazon wife; he "defeated" her on accident during a match with Ranma. Shampoo certainly considered an accidental KO from a sneak attack to count, so I'm assuming other Amazons might as well. And Taro is a really good fighter, a trait that Amazon women seem to prize above all others. Shampoo, at least, is willing to overlook all of Ranma's bad qualities because he's good at fighting, so I'll say that this woman did the same for Taro. She's just as power-hungry as Taro is, and helps him plot his schemes of vengeance and power, which often sound good but never actually work. Basically, they're they crazy neighbors that wake people up at night with maniacal laughter, and Ranma and Shampoo tell their kids to avoid.
Perhaps you could take it even farther. The Amazon he married was a childhood rival of Shampoo, and combined with Taro's hatred of Ranma, they've pretty much declared an unofficial bloodfeud against them.
I do like the idea Taro's relationship is still going, at least partially because his wife is as power-hungry and crazy as he is. Perhaps something of a joke is other villagers/Byankala natives commenting how surprising it is that they love each other so much- sort of a "match made in hell", if you'll pardon the term.
I'm glad you like my idea of making her parents power-crazed wanna-be super-villians SpaceKnight. You could have all kinds of fun abusing stereotypical "villain" behavior like plotting crazy schemes, maniacal laughter and giving them a habit of giving loud speeches explaining all if their ill-conceived plans. It's not even much of a change to Taro's character; in the manga he once proclaimed that he would take over the world with the power granted to him by massage beads! And of course, you could make fun of the fact that despite their grand ambitions, they're still pretty much your typical, albeit crazy, domestic family, and of how their daughter is embarrassed by their immature antics. That "match made in hell" line sums them up perfectly.
I think that's all of relevance for Lifen...
Water, water, everywhere, and all was cursed and black!
Drowned ones cast bad spell and out come pig, girl, duck, panda!
Swirl, swirl, slithery pond, and join with magic spring!
Swirl, swirl, dirty pond, and rid the cursed sting!
Here my prayer, I beg you please!
Now turn these curses BACK!
http://www.issendai.com/rpgs/japanese-boys-names.shtml
http://www.issendai.com/rpgs/japanese-girls-names.shtml