Is the legal recourse you are seeking to get out of the lease early? Or just to guarantee your safety deposit back?

The house we are living in has never been cleared by the city of Warren as a rental unit.

What leverage were you trying to gain? Getting the repairs done? It seems from your post that the repairs were sent to the owner any way. Try...

What do I do if I am being sued by a previous potential tenant in small claims court for a deposit back?

Is it possible for you to go to the court during your lunch break and obtain the letter? Try calling the clerk and asking. Good luck!

Can a landlord raise the rent without a new contract if it was not in his name in the beginning?

You say you have a month to month rental, was it memorialized in a lease agreement? If so, what does it say about rent increases?

If I file a CIV-100 and the defendant defaults, and it is for failure to pay rent? Is it required I fill out the form

You should consult with an attorney if you have this many questions about this process, mistakes can be costly and you need specific information...

Can a legit messenger service get in any kind of trouble by lying or committing perjury on their "Proof of Service"?

EVERYONE can get in trouble for committing perjury. PERJURY is a CRIME.

Does IL have a Late Rent Payment Agreement?

You would need to file a suit to be able to accomplish this.

I am a green card holder and will be flying tommorow evening back to my home country to study for 2 years

It would be best if you apply f or a re-entry permit which are fairly simple to get.

Query on H-4 to F-1 conversion while H-4 extn is on process.?

If you don't withdraw your H-4 it will likely be denied if your F-1 is approved beforehand

What if the same document overlaps at Green Card process?

Yes, the instructions do just that - instruct you on what needs to be completed and submitted.