You will run into some limitations if you attempt to use the “child relationships” function within the model builder. You can only include an object once, and you want to include it multiple times (once counting all records, once for each status value).
However, if you are willing to build this in a popup or a drawer, you could use aggregate models to create the summary values, and then bring them into template fields in your drawer. Look at the “Show Child Data in a drawer” tutorial.
