This is such a cliche answer! Ofcourse we know who the target customers are, funding would help in hiring and building more features. Thus increasing the value for the customer and the probability of success.
No, they typically have beta users and are already iterating on the product.
Be mindful that founders and their attitude usually count more than the initial idea to investors. Pretty much every product fails on first touch with real customers.
You've been quite snarky and/or arrogant here and that is a red flag.
https://startupschool.org videos are a good place to start. They are also available on YouTube iirc