When I first started out using this service, I also had a lot of questions and it took me a while to get it all figured out. So I will give you high level answers however I suggest you get on with chat to get all the specifics.
1. I need unlimited screens. I want to charge myself to my customers. yes, you can do this
2. I want to have a whitelabel solution where I can put my own logos so that customer do not know who is behind it. yes, you can do this
3. Since I have done whitelabel that means my customers will sign up on my website. So The whitelabel solution will be on your domain or I can integrate it into my own site.yes, the sign up process can be on your domain
4. I want to manage my customers accounts myself since I am charging them myself. So there has to be some way where I can manage every customers account and content individually. you can manage most all aspects of your customers accounts however I do not think you can use the application as a billing portal
5. If customers want they can login themselves and make changes to their content and make their own campaigns.yes, this is possible
6. I need to use my own android devices that I can manage remotely. Means, not just pushing the content but turn on, wakeup, sleep, initiate any other commands (which I do not know right now). A full control of the device. You will need to determine what features/components you are going to offer your customers as android devices do not offer the same functionality as windows devices.
Now, I have to buy Enterprise edition ? yes
Will it be cloud hosted?there are several options available however depending on your customer, you will need to determine which is best for you. And yes it can be cloud hosted by DS
Will it have unlimited screens or do I have to pay anything extra for the screens per month or per year?If you purchase that level, it will be unlimited
Are there any other hidden or extra charges for any other components?not within the software/hardware set
Hope this helps you with your endeavor!