That being said, most part time agents fail and you also have to think about your clients best interest.

Not only are they trying to watch out for there safety, but hey they are bringing up a very valid reason of up keep on your property just as if you had an appliance fail, you go fix it, but only this situation is more reason to give you more service/money made/good review if you show that you give somewhat of a care in the world if the people that are paying your bills are in good hands.

Otherwise if buyer fails to pay, seller has to incur legal expenses either to take back their ownership through deed or to assert a claim against buyers other assets (if there are any). 

I daresay that, for conforming loan, credit is pretty much pass-fail and not hard to get where it needs to be in most cases (my doing what I mention above)... but income is what really matters, once credit is "pass" how much will your income allow you to qualify for?

I'm a newbie to all of this and I will either fail or succeed ! 

If you fail to make your monthly house payments to the bank on time, that reflects on the Seller’s credit.

You're the one that will be paying the taxes, penalties, and consequences if you take this route and it fails.

I would give them suggested vendors, a consequence for failing to complete, a deadline to complete the work, and notice that I will inspect to verify the work is done to my satisfaction.After notifying the tenant, then I would contact the owner (phone or email, depending on their personal preference and my time) and let them know what happened and how I'm addressing it. 

The only thing you should be aware of is there is a section 8 specific inspection prior to move in that usually takes 1 month to complete so best case scenario is usually a section 8 tenant moves in in 2 months often its closer to 3 months if you fail the inspection and have to be reinspected which is common.

If you have a nuisance tenant (ex. tenant who pays rent but late every month, tenant who complains about things like "I saw A wasp or I'm getting the wrong mail in my mailbox,"  but fails to report legitimate issues in a timely manner, tenant who fails to get along with the neighbors), you won't be able to get that nuisance tenant out and all your good tenants will leave because of it.