(Base44 app): wrapper, native IAP, and push notifications for iOS/Android launch

Hi there,

I'm building an app on Base44, and I'm evaluating Median for the native wrapper ahead of an App Store and Google Play launch. Before I commit to a plan, I'd like written answers to the following:

Wrapper and native IAP

Total monthly or annual cost, and whether it changes between testing and launch.
Do you wrap our live Base44 URL directly, so content updates ship without a resubmission, or does this require an exported/forked codebase?
Can the app use our existing App Store Connect account? We're already enrolled in Apple's Small Business Program and want to keep that rate, not have a new account created.
Does the build include native tab-bar navigation and native location (not web geolocation), or just a billing bridge?
Do you submit to the App Store and Google Play for us and handle review feedback, or do we receive build files to submit ourselves? If you handle it, what's the process and typical timeline?
How does a native IAP purchase (StoreKit / Google Play Billing) sync back to our own subscription state? We need one entitlement that updates identically whether someone subscribes via Stripe on our website or via native IAP in the app, since we already run subscription automations off that entitlement.

Push notifications (OneSignal)
7. Which plan includes the OneSignal native plugin, and is that the same plan we'd need for native IAP, or a separate add-on?
8. Do we need our own separate OneSignal account, or is that provisioned as part of your service?
9. Can notifications be sent from our own Base44 backend function calling OneSignal's REST API directly, or is there a different recommended setup?

Timeline
10. Realistic timeline from signing up to a working test build we can verify on a real device, given we're targeting a launch before September 30.

Thanks,
Rommel