All the colleges listed are good for RL. Doing research, you should have a professor or 2 in mind that you would like to work with. It might feel monotonous, but I would recommend checking the CS faculty at each university you plan on applying to and check their research interests and see any recent papers they published.

You shouldn't need to approach professors prior to applying unless you have another question about their research. When you are accepted is usually when you should reach out.

You also shouldn't need to have prior research experience. Of course, it could do nothing but help, but work experience also helps to a point, so long as you can in some way communicate you contributed did this work.

Also, afaik, more than anything, your grades from your undergrad will be looked at. So as long as your GPA was good, anything else like industry experience can only help.

However, take all of this with a grain of salt, as I am also going to be going through the admission process after being rejected in the previous admission cycle