I've attempted to validate my business idea with a market research survey distributed to my target buyer persona.
The initial response from the survey is very positive, however, I've only got 16 responses (organic).
How much more validation would you seek before building the MVP?
What kind of market are you in? Mass or niche?
For mass you should calculate the testgroup size. https://onlinecourses.science.psu.edu/stat414/node/306
For niche you should really try to sell it before build it. There is no better validation than that.
If you have enough resources and believe in your product you can also build it and focus all your time on selling it when done.
in general I experienced that good ideas get positive responses when you ask around but once payment is needed or users need to install an app or signup good ideas fall apart. Very good ideas get you questional faces and a polite response, a longer than expected runway but when it takes off it can go quickly (Snapchat, Google, Facebook, Twitter, Airbnb, Cars, Mobile phones etc etc)