You can use different iPad models with it: iPad Pro 12.9, iPad Pro11 or iPad 10.9 (2022). iPad Pro 12.9 gives you the bigger screen but also cost more.
You can use up to 2 power banks to charge the iPad and to make the backlight work. 26500 mAh power bank lasts for 6 hours when charging the backlight only (can be more or less depending on your settings).
You can use any power bank for the iPad. For the booth's backlight, you need 15V(3A) power bank and type-c (both ends type-c) power delivery cable. Example 1 Example 2 Example 3
If you want to use the booth in a wireless mode, then you also require short cables for it. Cables will depend on your power bank. We mostly use type-c on both ends.