The only sentence which is completely wrong is the second one.

1 is alright. 2 is wrong, and 5 is the same as 1. 4 is actually a little bit wrong, the word "from" doesn't belong in there. Let's look at the meaning of these three sentences: 1. I am looking forward to my campus life starting tomorrow. 3. I am looking forward to my campus life which starts tomorrow. 4. I am looking forward to my campus life which is starting tomorrow. Numbers 3 and 4 mean nearly the same thing. I would use "starts" to mean a specific starting point or time, and "is starting" to talk about starting as a process, something that happens over time. Number 1 can mean the same thing as the other two. However it can have a different meaning as well. The phrase "starting tomorrow" can refer to the action of looking forward to, not the start of campus life. Let me give you a clearer example: > I will work hard at my new job starting tomorrow. Does the new job start tomorrow? Or has the job already started, and the person is not working hard already? So I would use sentence 3, or 4 if you remove the word "from". Sentence 1 is not as clear.