I guess I would say "equally or evenly" yoked for marriage to me would mean that you have the same similar belief systems. For example, a christian marrying another christian, a Jewish person marrying another Jewish person. Both individuals should have basic similar beliefs as how to live their lives as well as their own value system. You wouldn't want one of the partners to not want to have children while the other partner wants a large family. Some people may believe this term also refers to "race" but I don't agree with that just because the color of someone's skin may be different than another's. Each person's belief system would be more important to me than the color of one's skin.
When oxen are "yoked" it means they are together. They are joined and go the same way and do the same things. So it is with people. People who are "Yoked" have one mind, do the same things, have the same priorities in mind
Yes all of these answers are correct. Evenly yoked, is to be on the same page, or same level as the other person. You can't be evenly yoked if your girlfriends is a church goer, and you are a party goer; that would be unevenly yoked