I have few APPs sitting inactive one since last week, How much time it takes usually to get the api activated? how it works on subsequent requests?

I created one app last week and two today for my paper trading purpose.
I have few questions.

1. All my apps are inactive what is required from me to proceed, how much time it usually takes?

2. If once activated, on each new app request will it take same amount of time or it will activate it self as I have my previous apps active?

3. If I edit one of my active app for example to update return url endpoint or add/edit/remove web hooks, what happens to app status will it remain active or again i need to get it activated if so how much time I need to wait?

4. is there an api (sanbox type or demo api ) that I can use as normal but money in that would be virtual so I can do paper trade and using that api. No need to use any other platform?