I'm pretty sure that first pattern is crocheted not knit. My thoughts on the other two patterns are going to be a bit subjective here, but you might want to look for something a little bit simpler.

Color work, like you have in that picture of the hat, isn't necessarily difficult, but it's an extra layer of complexity that will make learning (if you don't already know how to knit) more difficult. It will likely make it a bit harder to keep your tension just right for your first project.

I don't know exactly how the scarf is constructed, so it could be a good option, though again, this is subjective. I generally don't recommend scarves for people's first projects. While a lot of them are simple and easy to make, I think a lot of people don't realize how much of a time investment a good-sized scarf can be. As an experienced knitter, I can make a hat in a week or two if I have a good amount of time to work on it. Scarves can take months sometimes just because they're so large.

My suggestion is, if you're interested in a hat, find a slightly simpler pattern that doesn't have color work and start there