Brand Strategy Phase ( Positioning your brand based off Audience research)
Facebook will only give you activity on their portal and will be limited to profiles that are semi-complete and may or may not contain correct data. It won't give you a full scope of what you want or need.
You don't want to use one tool but instead research several platforms to find specific information. Look at your customer avatar as a study where you are examining trends in the market as well as how someone responds to them. The study should include hard, factual information from research spaces as well as trends by groups of customers.
You will find that companies will offer specific information, such as median income ranges, types of careers, lifestyle preferences that you can add up to get a better idea about your avatar. It's best to break up all information you want to know about a specific segment, then use the research platforms to target the information and put your avatar together.
I can help you with your avatar and customer journey!