Minisplits with ratings for colder temperatures are available not sure if they are more pricey but mini splits in general if you need multiple heads can be pricey. 

If the area is properly temperature controlled and up to code with smoke detectors, is there anything else we should do/know to influence how this is listed on the appraisal?

The weather gets fairly cold in the winter and when the temperature drops to 5 degrees and a furnace goes on the blink expect to pay 200% more than the average cost for a repair, or pay for water damage caused by frozen water pipes.

I have a tenant complaining that the AC is not cooling when the temperature get around 90 degrees but it cools in the morning and the evening when the temperature is lower and also the walls are sweating for some reason.

However, on this 11th, via Google, I did not find the conclusions by anyone, that a series of plagues, going through the world, will be the new-normal, & to be a result of the earth's temperature to soon permanently rise one degree.

She says she has two running now and the temperature stays around 80.

Seal before the cold weather comes as mice will be driven to seek warmth as the temperature drops too.If the property is a row/townhome, check the neighboring homes. 

One flooring store said this might cause the planks to buckle due to seasonal temperature changes (didn’t realize we have seasons in Los Angeles, but decided not to bring that up!).

Essentially, make sure that the LVP isn't hitting any hard surfaces where it could buckle with temperature changes. 

Temperature is understandably a big issue for a tenant and you helped them solve that for only $220.