Thanks for the pointers to the autoroute functionality in KiCAD! While wiring manually is quite satisfying, this feeling vanishes quickly when changes in the underlying schematics are required!
Trees as shelter works as long there is water for the trees(evaporation cools, like in sweating). With increasing heat stress there is not enough water and the trees will simply die. Or burn.
What is the weight of one of these ear buds? I guess too much weight can easily give you head aches. On the other hand, it seems from the pics that further miniaturization is possible.