1) This is a thing I've wondered about for some time, and I assume you want accuracy.

There is no problem to snap to a curve/edge. You can try snapping via one axis (locked to an axis-up/down).

Select your object to move...
Right klick your targetobject, and go into vertice mode for that object...

Press "v" to snap to vertice, but MMB klick the "arrow", to start "axis lock", then simply drag your cursor over to a vertice on the target object... This will position your initial object to the same height as your target object.


You can also use the "intersect curve tool", to put "points" on edges, but I'm not sure if this is needed in your work. btw, you have to turn history OFF in order to work with this tool.