Questions and questions to make the jump from schematics to PCB

MarkT:

fungus:
On v2 the top layer track between Rn and Jn seems to pass awfully close to the opposite pad on Jn...

That definitely looks too close - design-rule-check should catch this though. Personally curved tracks like this
remind me of the old days where PCB artwork was laid out by hand using strips of black crepe sticky-backed
tape and a scalpel - crepe allowed the tracks to bend round without creasing.

Indeed, I have improved the PCB. Please see attached files.

By the way, when it comes to decoupling capacitors for ICs, can I consider this is as a special case and indeed route one pin of the capacitor to the IC's ground (as I have done in my PCB) or should I also route this pin as directly as possible to the global grounding point ?