"Liability reasons" does have some merit I suppose, as going to the property does increase your personal liability in some way (you won't be able to say you didn't know about an issue to avoid being found negligent, you might do something or say something while you're there which makes you more liable to be sued, etc.), but I would just call that a reason to be cautious and not say much while at the property, not a reason to never go there. 

The 5 unit my partner and I took over had a lot of negligence from the previous owner and all of the ac units should most likely be replaced so ~ 8-9 units.

Presumably you use a cpa for your taxes (or soon will) so the additional expenses of having an LLC will be negligible.   

If not, follow through with a Small Claims suit.Keep in mind it can be tough to prove they were negligent.

We already pay for utilities and internet and netflix, so the extra use is negligible. 

Someone slips and falls at property A due to poor sidewalk maintenance on your property (negligence).

The property manager not charging for cam for years would be gross negligence if it was in the leases.Property managers generally have ledgers they provide each month for base rent plus cam income and then expenses reporting.No legal advice given. 

If you provide anything in addition to the property being leased, and they can argue your negligence damaged their property (i.e. leaving an old refrigerator in the unit), they can make a compelling case that you're in the wrong when eviction time comes around.

shouldn't the appraiser been seen a negligent because he didn't actually measure the house?

There may have been some negligible settlement of the interior footings as well, but it is not noticeable from walking the floor.