As Mike has said, the reason you got no answer is probably that nobody felt they could answer it. But a few quick comments on this list:
I will list the information, so that anybody well versed in the android app developer programming may give an idea.
1. Does an app , need all the permissions of the android world to get it work?
What permissions an app needs depends on what the app does. No app needs every permission. Many apps ask for permissions they don't need (I usually advise people not to install apps that ask for unnecessary permissions, but you need to understand the permissions well enough to judge what an app might need).
2. When user give admin permission, does the device is greying the permission tab? I hope not.
I honestly don't understand this question.
It may be a Samsung software thing (I don't have a Samsung device, and they change the user interface completely), but I'm not certain what "permissions tab" you mean. In my system settings I can set or deny permissions for apps which I have granted device admin rights to just the same as I can for any other app.
3. Is there any sort of mechanism, on play protect scan, to check that only required permissions have been used by the apps in .
You mean do Google scan what permissions an app actually needs and reject it if it asks for more? No, they don't: there are definitely apps in the Play Store that ask for permissions that are not needed for their function.
4. We usually found apps are being deleted after users are affected by malicious apps, that were allowed by play google not at the time of install, but after use by the users as stealing personal information and advised to delete those apps
That is a statement rather than a question. But yes, when an app is detected to be malicious and Google realise this is the case they will delete it from the Play Store. They can remove it from devices that have installed it, but I don't know how often they actually do (they certainly don't do it in all cases). If you have actually seen this happening, and seen it happening regularly, then you are clearly browsing the wrong type of app because it isn't all that common.
Ok, let me come to the permissions of the app,
the permission the app sought are
Device & app history
Other
- bind to an accessibility service
- update component usage statistics
- receive data from Internet
- view network connections
- full network access
- run at startup
- draw over other apps
- control vibration
- prevent device from sleeping
- modify system settings
- install shortcuts
- uninstall shortcuts It almost has all the android permission list. Experts please reply
Er, yes. And? I've no idea what app you are talking about, so no way of judging whether the permissions it asks for are reasonable.