Drug Possession: Michigan Marijuana Possession, First Offense

My question involves criminal law for the state of: Michigan
in washtenaw county

So I got caught with 4 grams of marijuana in my dorm room. The officer said he seen me smoking out of my window. This was impossible because I was sleeping. This was at 4 am. The officer came to my room and bitched me out and said i was smoking and he could smell it outside. I just complied because I had marijuana in my room and else he would assume I was lying. Then they asked me if i had alcohol and i complied and they took 4 fifths of vodka. They didn't exactly say if they were going to charge me with an mip though. I didn't receive any paper citations or anything, but I think that it's because of it being campus police.

I'm a good student at university of michigan with no prior history.

I wasn't actually smoking in my room. Do you think the officer would lie like it may have been a setup or something at 4am? He said it like he really believed that he seen me smoking out of my window.

How much would it averagely cost in fines?

Do I need a lawyer or can I get a public defender? Not sure if I can afford one

I'm sure I will go through a diversion program. Will it ever go on my record?

Is there a way I can fight some part of it with the fact that I wasn't actually smoking if i could possibly prove it?

Also I myself don't have very much money. How much do you think it would cost to get an attorney?

Do you think I could get a public defender? is it worth getting a public defender?

I've saved up about 5k, but I still have to pay for school and I'm a college student. I'm listed as dependents of my parents for financial aid and they don't really have any money either. i have an efc of 0.