If all of these appeal to you I suggest going into one or two ( you can double major, but even that is REALLY hard to do) Narrow your major ideas down by thinking past college. What are you going to do with your Theater degree? What jobs are out there that need this degree? Research the subjects. Do you really want to take the LSATs and go to law school for an extra 3 years after your 4 years? Law school is extremely competitive also. Go to salary.com and look at the medium salary of each job in your area or where you want to work in the future. Sometimes majors appeal to you, but some aren't safe majors to take. I heard journalism was dying out, but I might be wrong. In my opinion, I say you look into forensics are law because they will best support you and your future. Maybe take some classes about some of these majors and see what you enjoy most.
First understand that saying "major in ___" is saying "I want to take 20 to 30 classes in ___" -- do you really want to take 20-30 (out of about 40) classes in theater or English, or are you just interested in taking some classes in those areas?
English, journalism, creative writing, etc... are essentially the same major in undergrad. They specialize more in the master's degree. You can major in English and will have plenty of opportunities for creative writing and journalism and probably some theater too.
"Forensic Science" isn't usually an undergrad major. You can major in physical anthropology, biology, chemistry, etc... and then study the forensic nature of the field in grad school later if you'd like. "Forensic" in college also means something different than it does on CSI on TV. Avoid the [anything/everything] Studies major option unless it's the best you can do because you can't get into the "real" major - workplaces (and other scientists) don't put a lot of value on those "studies" majors.
Law - again, grad school. Law isn't an undergraduate major, it's a professional school major for three years after you have a bachelor's degree. Your bachelor's degree can be in anything you'd like. You'll need an exceptional GPA, good LSAT scores, and solid writing and analysis skills.
Theater - "act and sing" is musical theater. Different major than Drama or Technical Theater. You can do that on most campuses without being a major or minor in the department. Just like "real world", they have auditions for parts and whoever is best gets the part. You can also take courses in the Music and Theater departments while majoring in something entirely different.
All of that said; in any bachelor's degree you will be required to take some courses in each of those things you have a particular interest in. Everyone takes English, Sciences, Math, Social Sciences, an Art, Government, etc... while earning their bachelor's degree. The question becomes which of these (if any) would you like to spend 1/2 to 3/4 of your college studies doing? Then it becomes, to what end?
One of the best ways to pick a college major is to determine what you'd like to do for a living in the 45+ years after you finish the degree. Then you evaluate whether that's a valid and reasonable career plan. (ie: people who are bad musicians shouldn't be planning to become pro recording artists, people who need to feed themselves and a family might reconsider being a novelist without some other sources of income, people who want to write for newspapers might want to see the condition of that industry, etc...) If you're insistent on living in a particular place then make sure there's a need for one of those where you plan to be. There aren't a lot of Egyptologist jobs in central Kansas. Nuclear Engineers work where there are nuclear plants. Marine Scientists don't do a lot of oceans research in the middle of Nebraska. It has to be reasonable.
If it is a valid career plan then you get a degree in whatever those people get degrees in, if they get degrees at all. If you hope to work as an accountant one day then a degree in English is not the way to go.
Now, if you won't be needing a job because you either already have a marketable skill or you already have plenty of money; then you can get a degree in anything you'd like. The purpose becomes different than needing to prepare for 45+ years in the labor force. Thing is, most people need a job when they graduate. Majoring in something that leads to jobs is a good idea for those people.
If you're not already wealthy or already vocationally qualified then don't rely on "but I love xyz..." yet; worry about becoming vocationally qualified first. After you have a job qualification locked in, then go study The Epic of Gilgamesh in fine detail if you want to.
That whole "study what you're passionate about lalalala" leads to very high unemployment rates because it leaves off the "...and there are jobs for those in the world."