A: Unfortunately not, every platform (Android, iOS, Windows) has own independent app store and except Android the license verification is done by platform (iOS, Windows), so it is not possible to somehow link purchases.
You will need to buy Neutron for every platform.
Please do not consider purchase for another platform as duplicate payment because every platform requires a considerable development effort to support it including: platform upgrades, API migration and compliance to some emerging rules and requirements from the platform provider (Google, Apple, Microsoft, ...) and etc.
If you purchased in Google Play but willing to use on Android device without Google Play services installed then treat it as a separate platform. In this case it is not a double purchase because from the development point of view we handle development of 2 servers and 1 web front end (Neutron Console), additionally we are running dedicated license server for that which is not free. So purchase via PayPro covers some of these efforts to deliver such alternative and keep it working for you 24/7.
And the last, by paying for a platform you support Neutron's further development!