For me to give accurate feedback, it's going to seem harsh but it has to be honest.
If you've never been part of an app development process, and you're not a developer you need a partner. You do not know how to manage risks you are unaware of or even what your MVP looks like... Forget about # of visitors, that's just some napkin math you did to see if it's worth thinking about but there's no real market research document you've created that explains this number so of course people are right to attack that figure...
Anyway... Let's talk first steps... Go way back to the beginning...
Who is your target audience? How many people are there? What need are you fulfilling? Where are you advertising? Why would they use your service?
Honest answers and detailed work on this may end up excluding you from developing the application and save you from waste of money if there is no real market value... If you don't establish this then you can just expect to spend a bunch of money on something that just isn't valuable.
So this is really basic steps, not super fun, nonetheless the beginning of the process and is most important to get right as everything else is aligned to that business plan. If you say like OR maybe about your features, then I say like OR maybe you shouldn't be trying to develop an app. How on earth can you hope convey to a developer, as a non-developer, what you are trying to achieve without very well-defined requirements? You can't. You'll end up with a shit product. I don't have a clue what your app is trying to accomplish.
Assuming you make it past that step and really, critically challenge yourself and still believe that it's a good idea, then you look at how to actually implement it and how to do that cost-effectively. You need someone who is a technology master to tell you that. Clearly, from what you've expressed, you're not the technology voice, you're the "business voice". Get someone that is not your prospective developer to do this. If the company you called to develop the app didn't tell you to do more work on developing the PLAN for the app, you can't trust them. They'll do a bunch of shit you think you want and you'll spend all your time with a headache figuring out how to control the mayhem.
That technology master will likely tell you that video streaming is complicated, but there are out of the box solutions that you will need to design a user interface around or you can implement it if you're quite good. This is basically outside of the scope for your minimum viable product. Don't waste time on this until you get some users and feedback from them to see if they'd use it.
IMO without plans, you'll be lucky to have 1k visitors a day within the first year. Also, with no monetary gains you will never be able to grow to get more users or sustain basic costs (especially with streaming or videos!!!).
