You can tighten or loosen opposing spokes to fix a little bit of runout yeah. I don't want to ride it too much missing a spoke though. I dunno, might just try to wait until the tires need to be replaced. Which at the current rate of tire wear shouldn't be too long. Rock eats these Dunlops.
And I clean the chain with the engine off. The first thing they pound into your mind in middle school shop class is to keep fingers/clothing/hair away from moving belts, chains and gears. People have lost more than just fingers making similar mistakes.