Your questions are interesting, but I think are for MUCH later than an idea. My new idea list starts something like this:

1. Does this product/service exist and pretty much solve my problem? Then use that.

2. If not... I am the first customer... I am building it for myself because I want to use it. (If it's a network product, then find a partner for the idea.)

3. Evaluate MVP do I find it useful, am I using it regularly? Does it solve the problem for me?

4. Introduce someone else to your product/service maybe a friend or family and get them hooked.

5. Evaluate engagement is my friend still using it ... am I still using it?

6. Build features for you and them.

7. Evaluate ... do you guys both love it?

8. Get some more friends using it... if it's great maybe you even start to get strangers.

Now get to your questions... how can I grow... how can I make money.