Hi! You can actually publish more than one prototype at a time with Justinmind, have a look at the section about how to use your online account: http://www.justinmind.com/support/your-online-services-the-basics/ It's also possible to buy multiple Justinmind licenses, have a look here: http://www.justinmind.com/buy-faqs.
I have used an app to set up geo-fencing for my children's smartphones. I set the school as the boundary. I will receive the email notifications whenever they go to school and when they leave. It gives me a lot of comforts.
Since it seems like you already have a kintone account, Zapier might be the answer for you. Zapier can integrate kintone and paypal to automate tasks. You can check the link below to get started. https://zapier.com/zapbook/kintone/paypal/
Send me a DM to discuss.
I have recently worked with another user and today launched the first version of our app EyePEC on Android
https://play.google.com/store/apps/details?id=com.rmgsoftware.eyepec