Ask HN: How do you understand user behavior/health and communicate with them?

Wanted to see if HN had suggestions for tools to get a good grasp of what all our users / customers are doing in our SaaS app, understanding how successful / healthy they are, and then communicating with them?

We currently use Mongo for our DB and Mixpanel for product analytics, which lets us see what specific events have occurred. But so far we haven't been able to figure out a good way to see things from a customer orientation, in order to answer things things like:

Which customers tried to use a specific feature today, which were successful in using the feature, and how many times did they use it?

Over the last week, which customers have not logged into our app, and therefore I should email them to figure out why?

Over the last week, which customers have logged in but not installed our app, so I need to offer support

Which customers were active last week but not active this week, and therefore I need to reach out and understand why? What are the email addresses of those users, and how can I reach out / email them with one click?

I can build dashboards for all of this, but are there tools to track user behavior like this, ideally with communication / automation built in?

Thanks in advance!