I'm struggling to see the exact question in here but I'll give it a shot.
Your minimal viable product should be something you can get users on and start getting feedback and start 'learning' as soon as possible. But you need to get that feedback and work on your next version at a regular pace.
Without getting users on to the system and using what you have you won't be getting that critical feedback. So it's important to get early adopters in and using the system. If it's of 0 use to them it's not an MVP. There has to be some benefits, but they will be wanting more. Have a way to collect that feedback, stay in close communication with them and let them know when the next features are available.
You will eventually have a product worth charging for. You can grandfather them in for free, or you can offer premium features that those users will want to pay for. There are plenty of options for structuring that.
37signals started having people on basecamp before they had the ability to collect credit cards (make money) - because they gave a 30 day free trial. So they essentially have 30 days to figure that out and make that feature.
Get users / community early.