Adding Edge Loop To Multiple Faces?

Support Basics & Interface
1

Is there a way for me to add an edge loop to more than one face? Or at least a way to edge loop one face without another?

2

not sure what you mean by first Q , edge will go over all faces in the loop, if it wont there could be a break in your mesh, it cant do adjacent faces
to stop an edge loop I just hide an edge AFTER where I want it to stop

3

Select edge ring, W -> subdivide.

4

Not sure about your questions, but you can do as heddheld told. Another method is the knife tool to manually add edges, press k. Or you can do a complete edge loop(shortcut ctrl+r) and then select unwanted edge then del(or x), select dissolve. With those methods ngons will be created …i usually try to avoid them.