I have thought of offering cash for keys, but think they would accuse me of bribery or something to that effect, even though that is common and legal if it is agreed upon between parties to my knowledge. 

So satisfying to create and witness the before & after.

Are they trustworthy and will I be able to witness, as such a young investor, large long-term growth for my capital as well as consistently  profitable cash on cash return?

Unfortunately, based on how the laws are written, I believe you will likely not have much wiggle room as otherwise you might be open to accusations of discrimination.Do your best to treat everyone well and understand the assistance you need to provide in order to help these tenants move to their new home.John

I certainly hope that no one would accuse me of doing anything illegal or immoral.

I’ve seen a number of accusations be tossed between seller/buyer when their not talking the same language.

I would always try and go in with a witness to prevent any false claims against you.Normal Access should be with 24 hour notice.

Does anyone accuse Mercedes of gouging its customers?

You can't know for sure that there is discrimination going on even though you are accusing everyone of this.The Landlord has every right to pick the most qualified candidate.

If you speak with the tenants directly just have the property manager there with you to be a witness so it isn't their word against yours.