Coordinates on clickevent
Try to "cast" it as a LeafletMouseEvent:
map.on('click', <LeafletMouseEvent>(e) => { console.log(e.latlng) });
The compiler is inferring that the event type is LeafletEvent, which doesn't have the latlng property. That's why you're getting this error.
The Leaflet docs indicate that this event is actually of type LeafletMouseEvent, which extends LeafletEvent. So, you can cast the event to gain access to the properties of LeafletMouseEvent (as demonstrated below:
map.on('click', (<LeafletMouseEvent>e) => { console.log(e.latlng);});