Quantity vs Quality of target users in idea phase

Hey everyone, my name is Kay. I'm working on a mobile app in the consumer productivity space for Android/iOS. My question here is around quantity vs quality of the target customers you talk to validate your idea and how much time you spend in this validation phase. I've done what I believe is my due diligence in the product idea research, validation phase with my target customers to confirm the problem/solution. My question(s) here are:

Questions:

1. How many target customers did you talk/work with to validate your idea?
2. How did you gauge the quality of your target customer? ( Some are much more valuable that others with regard to their feedback )
3. How much time did you spend on the validation phase?
4. How did you decide when feedback was enough to assess your idea?

About:
For some context, my app is a smart organizer that combines a calendar, tasks, notes, and other items into 1 place, allows items to be either private or sharable with other people. The approach/execution/UI/UX is quite different from my competitors.

Approach:
My approach was a combination of the following ( among others)

1. Quantity: Worked with about 1-2 dozen target customers
2. Variety: Talked to different segments age/gender/occupation/single etc
3. Events: Casually presented idea to people at various social events
4. Pitches: Made a few pitches / presentations to a semi-formal start-up group
5. Competition: Looked at reviews/ratings of all my competitors
6. Biases: Tried to present the idea as someone else's to avoid bias
7. A/B tests: Pitched the idea slightly differently at events to gauge responses

Any answers to my questions above, and / or further advice would be very helpful.

Thanks!