Hi Jon,
For future reference, it is best to separate multiple questions in separate posts... it aids other people in searching and also each question can be marked as resolved and correct answer.
Anyway here are answers to your questions:
1. Please read the PowerServer documentation set, it is covered: https://docs.appeon.com/ps2022/Load-balancing_PowerServer_Web_APIs.html
2. Please contact your sales rep since you have an existing legacy license they need to look up your license details and advise you accordingly. If purchasing new licenses, PowerServer is now licensed in tiers with no restriction on # of servers or test vs. production usage: https://www.appeon.com/pricing#powerserver
3. There are generally two ways to go about this:
a. Configure your project for your development environment DB connection when you are working in PB IDE. Then when you move it to other environments (e.g. testing, production, etc.), modify the DB connection info in the Applications.JSON file of the compiled Web APIs (no need to use C# IDE even though doc says so... just use text editor for the JSON file): https://docs.appeon.com/ps2022/Managing_database_caches_in_the_PowerServer_solution.html
b. Configure your project for all the different environment DB connections when you are working in the PB IDE. In other words, you will setup multiple connection profiles in your project object, but note that your machine must be able to connect to all these different DBs. Then in your code you would dynamically switch during runtime which DB connection your app uses: https://docs.appeon.com/ps2022/Dynamically_mapping_transaction_object_with_cache.html
Best regards,
Armeen
