yes, yes, and yes.
AT the top of you map, is a set of Buttons, one for OVERLAND, another for CITIES, and a third for DUNGEONS (plus others if you have the addons like COSMOGRAPHER, DIORAMAS, CHARACTER ARTIST, ETC.)
Once you start a Map, you can click on any of those buttons and it will bring up the drawing tools related to that package. Same goes for symbol sets, it's like asking if you can use a different FONT in a word document, it's just a feature in a map. You may need to adjust the scale for some things though, but they all work together in the same maps.