Terraria – What bullets and arrows in Terraria can penetrate enemies

This isn't really a problem with Terraria, its Hamachi not being able to get a direct connection to the other player and going via a relay.

Sometimes just restarting both Hamachi clients will fix the problem, but if that does not work you should forward the port Hamachi is listening on to one of you (Hamachi will try connecting from A to B and from B to A and only use a relay if neither is possible).

All of the comments you've received pretty much collectively give you the answer.

All of those enemies do spawn in 1.1.2; they're very rare, though, and require the right conditions/ biome to spawn. Water candles and battle potions will increase their spawn rate, but at the end of the day a lot of it is luck.

The groom spawns on the surface during blood moons, and Tim spawns at random underground (stone layer). Doctor Bones spawns in the surface or underground jungle at night, and more commonly during a blood moon.

So all you can really do is wander around, take advantage of the blood moons and of battle potions/ water candles, and hope for the best! You'll encounter them eventually if you keep at it.