I called immigration on somebody who I know is an illegal immigrant, I gave them the person's name, address, and social security # they were using. I feel bad now and I wanted to know the chances that ICE would actually respond and deport them because they are not a felon and have been in the U.S. for about 15 yrs. The second question I have is my cousin wants to marry her boyfriend who is an illegal immigrant and she wants to know if he can get a green card because of their marriage.

Once you reported ICE, your job is done. You will never get any feedback.

About your cousin, it depends on many factors, one of which is how he entered US. If he entered US without inspection, he will have to return to his home country while she files a waiver for him. This is quite a difficult process and they would need an experienced immigration attorney.