I can't comment on WolfCam but I wanted to say I have always seen Russia as Asian (although its culture is more European) and I have heard more people saying that. I have seen a few comments on JetPunk arguing whether Russia is in Asia or Europe (entirely).
I have seen JetPunkers argue about Kosovo, Vatican, Abkhazia, South Ossetia, Artsakh, and Transnistria as not being countries, and some of them would be disputably in Europe, don't know if that counts tho.
I considered adding those as well, but I decided to keep the emphasis on if it's European or Asian, not whether it exists or not. However, I do recommend my other quiz on the most argued topics on JetPunk.
The quiz is meant to focus more on countries where the country as a whole is argued to be (or not be) European. It's pretty agreed upon that France and Spain are both European countries, even though they have dependencies in other continents (similar to the UK and the US both having territory on other continents).
Yup! There's even a bridge spanning the two continents. But as you said, it's indisputably European. There aren't many arguments (if any) demanding Iceland be on the North American Countries quiz, and I have yet to see a map with Iceland anywhere but Europe
Technically, all of these countries (except for Armenia) are actually on both continents. Cyprus could be in one or both depending on how you look at it.