Part one:
Yes, put oil in first then put on a low/med heat. Generally cast iron should be heated gently, depending on your stove it should probably take about 5 minutes to get to a good temperature. The oil shouldnt evaporate - I've never experienced this. As to the type of oil - I use various depending on circumstance vegetable or olive usually.
Part two:
I generally shake the pan gently - when the oil becomes more less viscous (more runny) then it is at a good temperature to start cooking. You can also put something like a small piece of onion or bread into the oil - if it starts bubbling and generally cooking then its good to go. Some people use a couple of drops of water to see when it spits but I dont like doing this partly due to the safety factor and also due to the fact itll splatter over the stove top.
It depends a little on what you are cooking - if you are looking to brown some meat for example you'd probably want it a little hotter than if you were just going to make vegetable soup.
It would be the smoking point of the lower of the two oils.
There is a persistent myth among cooks that mixing two fats somehow makes for a better smoke point (usually oil+butter). But the molecules which will burn at 150°C will always burn at 150°C, no matter what other molecules they are mixed with. So, if you mix two oils, and oil X has the lower smoke point wlog, it will smoke at the smoke point of oil X. It will smoke less than pure oil X, but only because you have diluted it and you have less low-temperature-burning molecules in the pan.
This doesn't mean that the smoke point of your mixed oil is too low for frying. The smoke point of cold extracted oils is always low. But it is possible to refine olive oil, even though nobody sells it pure (the advantages of olive oil are removed by refining). If both oils in your hybrid oil are refined, it will have a high smoke point, suitable for frying. But marketing doesn't always care about such details, so, if they don't say anything more specific on the label, you can't know what kind of olive oil (or canola, for that matter) they used. From a cynical point of view, this is a perfect way to get low-quality olive oil, refine it, and sell it for frying hoping that the customer will choose the frying oil advertising "olive oil" among its ingredients, but there is no proof that this is what the producer is doing.
Best Answer
The smoke point of extra virgin olive oil is about 375F (190C), which is above the boiling point of water. Most likely the pan temperature is close to 350 or so for sauteing in the first recipe, or at least above 300F, so when wine (which is mostly water) hits the pan it starts to boil off, so what you are seeing is water vapor. When stock is added later it's still just water vapor. Once you add liquid the oil will typically sit on the top, which is the coolest place to be because of evaporation.
A big reason to avoid burning oil is that is creates off flavors which are undesirable, and the smoke itself is unpleasant smelling. For that reason if you want to do high temperature sauteing (think wok) or deep frying you would want to use an oil with a high smoke point, for instance peanut or canola (rapeseed).