Lenders also have a lot of other things they'll consider like:-Property Location -Local Economy/Population Trends (Figure you want at least 25k people or be nearby a city of over 100k)-Zoning - Building must be properly zoned for the amount of units it has-Experience (you have enough experience to qualify for a multifamily investment)The truth is there is no one size fits all answer because every lender has their own guidelines which is where a broker comes in handy. 

Hardwood floors, stainless steel appliances.

As @Chris Clothier and @Curt Smith have pointed out, there is a lot of good data on economic and demographic trends readily available.

Recently, I'm noticing a trend of more and more probate and trust listings hitting the market. 

I previously owned a fitness studio for 3 years and worked at a steel mill 7 years prior.

If every rental in the nearby area has granite countertops, stainless steel appliances, and washer/dryers, you wont be able to charge as much as them unless you put in similar finishes.

Everything is going on in the market.Charlotte has one of the most active RE markets in the US.This is an extremely broad question, but some basic economic research on RE trends for the area should paint a good picture for you.

I like how his analysis of demographic trends point to sustained/increased demand for multi-family and rental properties in the future. 

They're not doing so hot, and many of the out of state investors come in breathing fire and run out in the middle of the night white as a sheet and in quivering fear someone will hear about the shaved Steel City orangutan they woke up next to.

When I exit, then I'll do upgrades to make it match current market trends...