[icingdeath88]

Smoke at startup can be bad valve stem seals. They can get dried out and start to leak. Usually happens if the car is sitting for a long time. The oil seeps down while the car is sitting and then gets burnt when the car starts us.

A small amount of condensation is normal when the exhaust is still cold; burning hydrocarbons produces CO2 and H2O. When the exhaust warms up, the water doesn't condense, but the same amount is produced. A coolant/headgasket leak will cause an abnormally high amount of water, but this is usually evidenced by white colored, coolant smelling smoke. I don't really know how you would quantify what is normal or not, but if you're not losing coolant from the radiator, then I wouldn't think that's your problem.

Bad headgaskets are another possibility. That can cause overheating, grey/blue smoke (burning oil), white smoke (burning coolant), low compression (hard starts, and low performance maybe).

The buzzing is probably the exhaust heat shields. My black car does this and that's what it is. I wouldn't worry too much about it. If not the heat shields, then it can be the cats.

Check if your crank pulley is separating also - search on how to do this. The knocking, you just have to try and listen and see where it's coming from.

As for starting problems: check the code that the CEL is throwing... (see how-to docs section). Coolant temp sensor very often causes starting problems and what you said about the radiator I didn't quite understand, but it is worth a check. I don't think it always throws a CEL, so even if that's not the code I would still check it out. Check the code.