Imagine you're assigned as a developer to this project and you have to make the first step in refactoring of one of these classes (choose one, by the language you're most comfortable in). There are many issues in these classes, even though they compile and work.
Please, submit a pull request with the changes you would recommend to do here. Try to spend 15 minutes maximum for the entire work. If you need more time, you're doing something wrong. Remember, you have to do just the first step in refactoring. Don't fix everything.
Also, if you think that something else must be refactored further, put your ideas into the description of the pull request.