This thread is meant to be locked. I will ask a mod to merge this with the ruleset discussion registry.
1.6: Correct.
1.7: You can do the trade you mentioned. 1.7 is to protect people from saying "move 2NE, 3S, and 4NW to reach Civ X" until they get either Navigation or Printing Press.
1.8: You are better off abandoning your city and letting the other team build a city there, rather than giving them something for 20 turns. This was a touchy issue in the ISDG. I would prefer no city trading unless it is a peace deal. This will go on a case by case basis. 20 turns is a LONG amount of time.
You can say "hey, we live southwest of you", but not grid coordinates, screenshots, hand drawings, etc. A simple direction is the most until the tech. Don't say "lower left", rather say "southwest" so they don't know exactly where. But then again, do you really want them to find you without you finding them... ?