How to choose a pan for making caramel?
You ask about coating, but it is actually not very important. There are other criteria with much higher priority when you are making caramel or other types of candy. The important thing about pan when making caramel is even heating. Especially when making your caramel dry, you cannot afford hot spots, because you cannot stir. But if you are taking the candy into the later caramel stages, even heating becomes important for syrup-started candy too. 

You need a responsive pan if you are making caramel. Sadly, the most evenly heating pans are also the least responsive and vice versa. I would never make caramel on a resistive stove in iron, but I use a small enamelled Dutch oven for caramel on my induction plate. A good sandwiched steel with an aluminum core should offer a decent tradeoff between evenness and responsiveness on most stove types. 

You also need the correct size pan. If your caramel is less than 1 cm deep, it is very hard to handle without burning it. If it is deeper than 5 cm, there is too much of a heat gradient in the depth. Choose the pan diameter such that your caramel depth will be between 1 and 5 cm roughly. 

If you are going to add any kind of liquid to the caramel (or butter), you'll experience lots of foam. You need a deep walled vessel to catch this foam. Use a deep sauce pan or a small pot instead of a frying pan. You want 10 cm wall above the caramel level. 

Aside from a seasoned cast iron pan, I haven't experienced a coating adsorbing flavors. PTFE, ceramic, enamel, anodized alu or no coating - none of them matters. Use whatever you have handy. For cleaning, follow Elendil's advice for dissolving the smears in hot water.