No Problem!
Antique Coins - I did a quick check and antique coins are not bugged. I think it must just be really bad luck. They have a very low chance to drop, but I haven't changed it since the first release.
Black Fur Drops - How many wolfkin did you need to fight? I wouldn't want to guarantee the drop, but I could increase it for a future update.
Gargoyle Fight - I tried it again and yeah I have to agree. I'll be pushing another update with an overhaul to the fight. Thank you!
Run Mechanic - I was actually thinking about overhauling the run mechanic for the next minor update. It won't be guaranteed, but your next chance to run will increase with every unsuccessful attempt.
Ghost Elfs - They can only be damaged by a weapon that does Shadow Damage.