Takeda Classic Mini Petty 100mm
Richmond Fanatic Thin Cleaver
Sakai Takayuki Damascus 240 Gyuto
All are pretty solid choices.... and the ones they liked! So it is hard to go wrong with that.
BUT... I was once inexperienced with Japanese cutlery and made some purchasing mistakes, and there are things you should know.
The Takeda is carbon and has a certain amount of upkeep you have to be sure she is prepared for. Lemme guess, it was the heart on the blade that sold her? At 100mm, it is a bit small. It will perform well, but she will probably want something more versatile. Get something at a larger size. 120mm-150mm would be ideal. Plus, it's uber expensive.
The Richmond Fanatic sounds like a solid choice, but a nakiri would be a better choice. It will perform just as well, and it is lighter & easier to handle. Although smaller, she could always grab her husband's gyuto when needed!
The Sakai Takayuki is a great knife from what I read on the forums, but what knife is he currently using and at what size? If he is using a western-handled knife at 8 inches, I would definitely get him a 210mm with some belly.
For the fiance: http://www.chefknivestogo.com/kar2pe15.html
For the mom: http://www.chefknivestogo.com/riarna17.html
For the dad: http://www.chefknivestogo.com/masamoto- ... 210mm.html
(looks a lot better than pictured) or http://www.chefknivestogo.com/kiswwadagy21.html
As for you: can't argue with that choice, just make sure you choose the right size.