"The most important thing a father can do for his children is to love their mother." -Theodore Hesburgh
The bread-winner of the family, he's generally fairly calm, more level-headed and dependable than the female members of his family. He's crazy about his wife and daughter. He drove into DarkTyrannomon to try to protect them in a sudden display of aggression. ^_^;
(I think Mimi's dad is extremely cool, and kind of funny. Heheheh.)
It's obvious where Mimi inherits her personality - although by this time in the story, Mimi has grown to the point where she seems more mature than her mother. ^_^;; Mrs Tachikawa is exciteable and a little silly, kind of childish, prone to hysteria and tears... but also very kind and encouraging and eager to please people.
Here's a little piece of dialogue I liked. They're being kept in the convention centre.
Mrs Tachikawa: I just can't stand this place one second longer!
Doesn't she sound just like Mimi, in a weird sort of way? ^_^;
How we see them
In the real-world saga, Mimi is the park with Palmon, then she sees her father who was working late, and walks home with him, smothering Palmon. ^_^;
We see Mimi's mother feeding some sort of weird dessert to Mimi's father, and both of them babbling happily over each other, like newlyweds. Mimi's mother sounds very happy that her husband likes her food. ^_^.
Later, Bakemon raid the apartment, and the three Tachikawa try to escape, but I guess they are rounded up, because the end up in the convention centre with the other prisoners. Mimi manages to sneak Palmon in with her, though, which is lucky.
Mimi's mother does not respond well to being held prisoner and freaks out a lot, crying and screaming, before smiling brightly and saying that she felt much better after getting all that out of her system. (Sora seems impatient with Mimi's mother, just like she used to see Mimi. ^_^;) Her husband is generally more calm.
After Sora uses Joe's technique to free everyone, all the trapped people start to pour out of the convention centre, but there is a DarkTyrannomon there ready to attack them. Mimi's father drives a golf cart (^^;) into his leg, claiming that "you couldn't be in safer hands". Seconds before getting smashed away. Palmon digivolves to fight, but she isn't strong enough.
Mimi and her mother rush to their man and help him up, Mimi's mother saying how that was the bravest thing she's ever seen and they go all gushy again. ^_^. But there is still the threat of the danger, and Togemon is losing. Mimi is desperate to keep her family from being hurt, and to keep Myotismon from winning, and the sincerity of her feelings cause her crest to react for the first time. Lillymon easily defeats DarkTyrannomon.
Later, the two are held under Myotismon's spell, and after they come to, they go back out into the city and see Mimi going off into the sky to the digital world. They call goodbye, then watch the sky until Apocalymon is defeated. (Mimi's mother is crying by that stage, and her husband holding her.)
Mimi's family live in an apartment, they give Mimi a reasonable amount of personal freedom. They don't bat an eyelid when she announces she's going to dye all her clothes pink. ^_^;; Mimi's bedroom is pretty fancy, too - she's probably a little spoiled, and used to getting what she wants. Her mother also often orders takeaway rather than cooking.
Like the quote at the top of the page says, I think it's good for children to have parents who are loving towards each other - it gives them a good example. It probably also accounts for why Mimi is not afraid to show emotion and to express her affection more freely than any of the others.
Mimi seems to get along with her parents very well. They all love each other very much. Mimi and her mother are similar in personality, and I think Mimi is a bit of a Daddy's Girl. ^_^.
They supposedly have a dog, but we never see it. It's probably just another one of those comments that is never proven.
In 02, they seem to be happy to let Mimi (who is 13 or 14) travel overseas by herself. They give her some independence and raised her to feel loved and sure of herself.
Mimi also mentions a baby brother. However, this is early in the series, and a few times early on, people mention things incongruent with what is later shown... for example, Matt says that he and TK are half-brothers (which they aren't), and once says something that implies he lives with his mother (which he doesn't). Tai mentions a puppy he doesn't have. And so on.
I'm just saying that apart from a fleeting mention, no follow-up is ever made that she actually has a brother. He is never talked about again, never shown, and I don't think the Tachikawa would flee their apartment and leave him behind, do you? ^_^; Plus, on the sign the Tachikawa have on their door (there's a pic of it at the top of the page), there is no baby brother. AND, Mimi does seem like the sort of person to be an only child.