No. Bifrost and NativePHP are two completely separate products and in no way is Bifrost required to use NativePHP. Bifrost is a service aimed at streamlining your workflow.
Build credits allow you to run builds, whether it's an OTA, macOS, Android etc.
Credits create predictable bills. Instead of metered usage and possible surprise bills, you will always know your expenses with Bifrost.
Your monthly allotment of build credits do not rollover, however purchased credits never expire!
For a Max license you will want Hela or Thor because they allow you to manage unlimited apps. If you need access to team features or priority support, then we recommend Thor.
You can purchase additional build packs at any time. Build addons don't expire and can be used whenever you need them.
Yes! You can upgrade or downgrade your plan at any time. Changes are prorated automatically.