This is a bit out of date. These days basically any ATM allows foreign cards, just in time for Japan to finally switch to electronic payments in a big way (in particular PayPay).
> These days basically any ATM allows foreign cards
I thought so, too, and perhaps it's just bad luck, but I was at Tokyo Station a few months ago, and I wasn't able to withdraw cash from Mizuho Bank's -- one of the largest retail bank in Japan -- ATM from my US debit card. I ended up walking (getting lost for) ~10 minutes to a Seven Bank ATM, and withdrew cash there without issue. So YMMV.
Most let you use them, the post office and 7-11 had the lowest fees
Yes. The payments landscape has shifted pretty dramatically in Japan over just the past 3 years. It used to be that you had to worry about getting cash, IC cards, refilling said IC cards, going to an actual bank with your passport, etc. Now all you need is an iPhone (although I hear Android phones from outside Japan still can't use suica).