hey i will do my best to answer your questions as i can:
about eating locally- i just read an article about a couple who pledged to eat locally for a year. they ate foods grown within 100 mi. of their home and there were times when they were limited to a couple of food items and lost lots of weight. as variety is of utmost importance in macrobiotics, im not sure how realistic it is to think you can eat totally macro and also totally or even a majority local. a good thing to strive for definitely, and it also depends on where you live. im sure youve read macrobiotic books but im sure they discuss this. there is some sort of chart that lists the best sources of each category of food for example, fruits and veggies should be local as much as possible, but sea salt should come from the hemisphere you live in. im not sure about the other categories, but as you go down the list of food groups(fruits and veggies, sea veggies, grains etc) the geographic area spreads out a bit. there is probably even something on this site about that, though i havent looked yet.

when it comes to pickles, any good quality saurkraut should do. i use edenfoods or bubbies, you can also make your own, as well as your own pickled veggies. pickling is basically sprinkling salt on veggies(carrots, cabbage, daikon etc) and pressing them to release their juices, this can take anywhere from an hour to a few weeks. again, variety is better
when you talk about japanese pickles do you mean kim chee? im not saying you cant use that, but ive never read about it being used in macro, its usually spicy and i thought spicy is generally considered too xetreme for macro.

sea salt- for grains i add a pinch after they begin to boil and to taste when it comes to soups or gomashio, when i become stricter i will probably make things slightly less salty than i would normally like in order to get used to that. i think it depends on your constitution when it comes to the amt of salt you need(a large full grown active man needs sig. more than a childetc.)

potatoes- i thought they were generally not eaten in macro-you could probable use other root veggies for thickeneng or else purreed rice? good luck and let me know if there are other questions you have.