chEAR squad is really a mini merchandise package that includes access to a reserved section of bleachers at the finish line. It isn't necessary to have chEAR squad to cheer on runners. There are non reserved bleachers and standing room at the finish area that anyone can use. Tracking will be available on the runDisney site as the race gets closer, but that will most likely just get you a 5k/10k/10m/finish splits at best. If you want something more accurate your runners would need to have a GPS watch/app that lets you live track them.
As I believe that Dark Side is using a new course, (Start is listed as being on Floridian Way) view points will be up in the air at this point. To get to the start line to cheer on you will need to take the runners transportation in the morning (bright and early). There should then be transportation to the finish area, or they may point you to the TTC to take the monorail over to Epcot. If it goes through MK you can cheer on Main Street, but thats the only park you can cheer from w/o a ticket, and potentially the only park runners will be while it is open other than the last runners going through Epcot. (5:30 start, 3 1/2 hour max on course time, allowing for 45 mins or so for the last runner to start, means course should be clear by about 9:45) I'm guessing the course will go through MK, DHS, and then finish in Epcot. If it does go the way I think it will, the most numbers of times you may be able to see your runners would be at the start, then you walk over by GF/Shades of Green and then head back to TTC to take monorail to finish. If it does go into MK, you would need to go their first to get a decent spot, so you would most likely only be able to see them there and then at the finish.