Toyota yaris misfire/coolant leak

[jaybowblue]

I'm experiencing two issues with my Toyota yaris.

1. 3rd cylinder misfire
a. replaced sparks and coil but still misfiring
b. seems to be a bit rough when starting but generally drives fine without issue.

2. overheating
a. seems to be an antifreeze leak, right under the engine, i can't quite tell where its coming from other than that
b. I just had the headgaskets replaced, i don't see any over white smoke in my tailpipe and i don't typically smell any antifreeze. Had the guys who did my headgaskets run a compression test and it came out fine

Any ideas on where the antifreeze is leaking?
What do check next for misfire? it has been suggested i consider replacing the fuel injector.

[jaybowblue]

Felt like i should add that i had the water pump replaced when i had the gasket done in case this was a suspected coolant leak location.

[jaybowblue]

The random misfire is still unexplained however the coolant leak is coming from a missing bolt in the back passenger side of the engine.