late to the game but to add:
One important thing to note about working in Japan is visa. Your visa is not tied to your job so even if you quit you can move around jobs or start your own company. This visa situation is the opposite of America.
Rent is proportional to location but in general train in Tokyo is excellent so you can live in outside Tokyo like Saitama or Kanagawa and still be in downtown Tokyo in 20-30 mins.
I'd say the minimum salary to live comfortably in Tokyo with a wife and kid is 300k yen / month. You can see there are students who live with families with only 200k yen / month and still afford to go home to their countries once a while.
If you can read Kanji, you will have easier time adjusting. At least you can read all the documents and instructions even without being able to speak. My coworkers are Taiwanese who don't speak Japanese anyway.
You will have to pay into tax, health insurance, and pensions which are calculated from tax. If you want to reduce the tax then you should start at least an own business like sole-proprietorship.Yes you can do it even while employed at another company. With a business you can turn some of your bills into expenses. Some people start consultancy or private english teaching for this purpose. Of course you will need to take care of your own accounting.
Work culture really depends on what you do and on companies. If you are software engineer you can even work remotely. If you are in the management / accounting kind of work then it will be typical office hours. If you work in big old Japanese companies then you will probably do a lot of overtime.
You may have some difficulty renting an apartment. Landlords can and usually put impossible conditions to foreigners (like having a Japanese relative as guarantor), essentially soft-banning them. So we can't be too picky with apartment. Also the government has recognized the problem. But what they do is run their own rent agency called UR Housing. Apartments listed here are available for foreigners without crazy conditions as long as they have income (or something around $50k savings)