Per q1, Meetings at my organization currently tend to be pretty freeform, so I can't say if it's a problem that really needs solving, though I'd personally appreciate if things had somewhat more structure as described by your MVP.
Per q2/4, without signing up, it's not entirely clear. I'd recommend the getting started page either having more detail or having a learn more page which shows the workflow your application provides with basic screenshots prior to requiring a sign up. As per the application itself, the way you describe the 'WHAT' here seems like you may need to be cautious about the scope of the application. Typically organizations will have existing tooling for meetings to occur in (just a normal conference room reservation, slack, teams, gotomeeting, etc, etc, etc). The pitch of the idea seems to have your project being an organizational tool on the side, so creating meetings/inviting individuals is likely being done elsewhere and the tooling you provide would fall into managing the flow of the meeting.
Per q3, given that meetings are not currently managed in this style my current org would likely not use such a tool even at no cost.