Every Sheriff's department interprets their duties in an eviction based upon past consequences. 

Paint, floors, finish plumbing & finish electric, trim, etc ... cosmetic stuff you can do yourself, since the consequence of doing it wrong is not as great ... worse case is you redo or touch it up.

If I'm planning on profiting as much as possible on these properties and then sell them to trade up anyway, wouldn't it be better to do a 30 year for the lower monthly expenses even though it may kind of tank my equity when it comes time to trade up?

I would probably do your first deal by yourself to learn the trade, and then once you understand the ins and outs, go back to him for a future deal.

What about selling a valuable piece of art or trading card.  

If you go with a pro they will knock a tube out in no time, but your other trades won't be able to enter, or at least they should not, for at least a day.  

If so it is hard to convince tenants that they are late since there is no consequence to being late.    

I don't know of any job or trade or profession where you don't need to adapt to new things, changes in an industry or practice, so education is always an ongoing process. 

"Normal" people are just as capable of trading in a car with a payment and buying something that they can afford to own...rather than afford to make payments on.  

And what happens next will determine how severe the upcoming recession will be.Wise developers, noting the change in direction of rent growth and factoring in the likely consequence of units currently under construction being completed, should choose to stop building.