In addition to the tooltip, could you add a feature to display a label above the mark? Select font attributes and the properties (concat in order selected).
There are actually several questions in your issue:
Having a label above the marker: this could be done easily by having tooltip (or popups) displayed by default
Adding more data to the tooltip/label: this is doable, we just have to think about where it should go in the UI, probably that can be a hidden "advanced configuration" box close to the tooltip property label input
In addition to the tooltip, could you add a feature to display a label above the mark? Select font attributes and the properties (concat in order selected).