Will I lose my subscribers and analytics data on Spotify/Apple podcasts after migrating?  

You will not lose your subscribers and analytics data on Spotify/Apple after migrating if you follow these steps:

You can seamlessly migrate your subscribers on Spotify for Podcasters by logging into your account and updating your podcast RSS by adding the Hubhopper Studio RSS feed in place of your old RSS. Your RSS will get updated and your subscribers will continue getting updates for new episodes on Spotify. 

Similarly, for Apple Podcasts, you have to log in to your Apple account and update your podcast RSS feed with the new Hubhopper Studio RSS feed.