In my case, they denied me primarily because I didn't have at least 2 off-street parking spots per unit (4 total, in this case), and although there is a 2-car at the property, they wouldn't even count that, leaving me with 0 off-street parking spots in their eyes.They had some other reasons as well, but off-street parking seems to be a favorite of municipalities around here to quickly DQ such a request.

Does every potential tenant go through the full application process or can you deny them just based on the prescreening?

So unless you are moving further away from your current home (Typically 50 miles if I remember correctly) than it will be something that the underwriter questions and may deny the loan due to the suspicion of mortgage fraud.

however I feel he would try to find roommate or something, since there is nothing mentioned related to it in lease , can I just deny saying sublease / roommates are not allowed.

It's my understanding that a bankruptcy isn't required for a short sale, but once a bankruptcy is started a judge can approve or deny a short sale from taking place...is this accurate? 

He's trying to rent an apartment and got denied because the leasing office said that UBER is NOT considering as a real job even though he have a 1099 and pay taxes.

For all applications I receive but deny the tenant, I need to send them an adverse action letter via mail detailing why they weren't selected?

Over 50,000 applications for assistance were denied in NY alone because applicants couldn't show loss of income.

I have a house that I applied for a building permit, after waiting for a couple of weeks I called up the permits department only to find out I was denied and they sent everything back which I included copy of the deed showing I was the owner, Class A license, Scaled Plans.

You cannot deny the family because of the lead paint either, that's considered discrimination (you're refusing them because they have a kid) and is against the anti-discrimination laws of the state.