Perhaps you should consider hosting a smaller scale tournament first? You're aiming pretty high for a first pitch and you may be disappointed. I think the involvement of money in your pitch for this one is not encouraging for a startup organiser and you will need some practice to avoid technical issues, to get used to the quirks of the game and to establish yourself with the reputation necessary to draw any significant number of participating teams.
Additionally I'd suggest that you'd make all information about your tournament available on this forum. You'll have enough issues trying to organise a tournament with no prior reputation or experience without making potential participants jump through unnecessary additional hoops. It may also be worth looking into streaming via Twitch, whether you look into doing it yourself or contact established casters. A Twitch stream is a pretty standard expectation for any competitive event now.
Finally... well. Even if we ignore the issue with your inexperience: you're too ambitious. To put it simply, competitive GOIO rarely draws any significant attention beyond the teams participating. I'd be highly surprised if any number of people were willing to involve money in the competitive scene. Forget ad revenue. You will not get that many views, you will not become famous. If you do an excellent job, participants will probably be grateful and think more highly of you, and that's about it.
As for the profit sharing with charity, I too don't really see the need for tangible prizes or any kind of money split. Give it all to charity, or better, don't ask people to let you handle their money at all. I would much prefer to see you show a feature on the charity with each match to encourage people to donate directly; that way you aren't casting doubts on your own legitimacy by asking people to give you money, yet will still be supporting a good cause.
