If you need a physical SIM then I'd advise going to Bic Camera or Yodobashi when you arrive.

Getting one at the airport is convenient, and not so expensive, but I picked up an unlimited LTE data plan for $20 for 30 days, extendable for 3 months, all instructions in English.

There is no issue at all with writing you delivery instructions in English if you need to mail items, Japan Post and all other couriers completely understand the addresses in English.

Because you cannot buy a SIM with phone or SMS access, only data, they don't even need your name or any ID. Just put it into your phone and if needed choose the APN. I've got a dual Sim phone, so use the foreign SIM for receiving calls, and use the Japanese one for data and sending message and making calls with Skype.