Other workers have Unity Pro with Android and iOS add-ons. Do I need the add-ons if I'm not publishing the final install files?

I am about to start a project in Unity and I'm looking at the licenses I need to buy. The project that I'll be working on has a prototype developed with Unity Pro with the Android and iOS add-ons. I know that I need a Unity Pro license to work on the project. Do I need to purchase the license for these mobile platforms as well to be able to work on the project? If I don't purchase the mobile licenses will I be able to create the mobile install files (.apk, .ipa) but with the Unity splash screen or will the install file creation be gone completely? I believe things are a bit different now that Pro features are free. Thanks.