I am trying to add a wms tile layer overlay over a wfs tile layer which I added to a map object. When I tried to simply add a layer on top of my current setView for my map object it overwrote the first layer's and all the GUI I added was gone. How do I add a wms tile layer overlay?
Have a look at the example on this page: http://leafletjs.com/examples/layers-control.html
It is definitely possible to add more than one tiled layer, like they have done. They are using L.TileLayer in this example, but you can use multiple L.TileLayer.WMS instead.