Using Skype Online Number in Japan

My friend and I will be traveling to Japan for 2 weeks and we will be sharing a rental pocket WiFi.

Assuming that we got separated in Japan and I am the one holding on to the pocket WiFi with a laptop, can my friend use a public phone in Japan and call me using a Skype Online Number?

We are trying to save some $ by not getting a rental mobile phone in Japan.

She should be able to, but she'll need to do an international dial to your skype number.

Alternately as a backup in case you get separated, is setup a specific meeting location to meet back up.

It probably seems better to do that, then stop turn on your laptop and wait for a phone call.

yes. viable option is purchase a 1 month skype- in number, choose a local area code or a mobile code in your destination. Your friend can call using a public call phone- costs one or few 10 yen coins depending on length of call.