As far as collecting an additional $200 per month from someone who is on housing assistance, in this market a lot of Landlords flat out reject the notion and would deny the applicant.

If they deny our request then the deal is done.

Per the lease if it stipulates the landlord has a right to enter the premises with proper notice to perform an inspection of the unit then it's valid.A tenant with a lease cannot keep denying a landlord entry into the property for inspection.

Can anyone agree or deny these claims from personal experience, and if so suggest other areas to begin searching?

Credit card companies can deny these checks.I Never use all of my available offers at the same time because I might need to transfer a balance in 15 months if something awful happens. 

The bank will usually stand behind a pre-approval letter for 60 days or so but remember, it's not a guarantee that you'll get a loan, just that they've checked you out and so far there's no reason they see to deny you a loan.   

If you're using an FHA loan make sure that the total monthly payment is less than both ( duplex ) market rents or your loan will get denied. 

At the very least, you need to read up on your local laws regarding tenants - you should never have your tenants telling you what the laws are .. and then you not being able to confirm or deny it - they can sense that you don't have a complete grasp on the law or the procedures so they are taking advantage at every opportunity and have been bilking you for months.

My parents Want to get a Loan for land. it is under 50k but despite my father having decent credit( they require over 700 for all 3 scores and 1 of his is over 700 while the others are high 600's) they denied him the loan.

If you deny an applicant or take any adverse action (i.e. charge higher security deposit, require co-signer, etc) based on information in their consumer credit file, then you should be sending them an adverse action letter which basically tells them what consumer reporting agency supplied the info you relied on, the contact info for that agency, and how they can get a free copy of their own credit report.