Hi @Prosind,
Yes, you are correct, SQL will require Premium. There are 3 ways to get it covered: per-app plan, per-user plan or Pay-as-you-go.
In your case, a Power Apps per-app plan makes perfect sense as the scope of users is clearly defined and you have a very small set of apps on the radar. Here you can find more guidance on how to setup it https://docs.microsoft.com/en-us/power-platform/admin/about-powerapps-perapp.
If you are going to have more than 1-3 apps, consider shifting to the per-user plan which will open unlimited amount of apps for each user with assigned license.
Consumption-based PAYG option is not considered here, as it will require you to have an Azure subscription and it is more suitable for large businesses starting utilising Premium Power Apps but not ready to make a high initial commitment for subscription-based plans (per-app or per-user).
More on licensing here
https://powerapps.microsoft.com/en-au/pricing/
In summary, start with per-app plan and then consider shifting to per-user if your apps portfolio grow over 2-3 apps. Hope it helps.