They typically have a "designer" or "consultant" for free that can give advice (or research in your case) specific items.

Many companies I found do not want to cover a lot of homes because of the items you stated but with that the hurricanes and also in florida many roofing companies have done the "I will replace your roof for free, just let me deal with the insurance company".

simple math, compare the cost of the total payment now (pi +pmi) to new (pi) and see which one is lower.

I just looked at a utility bill with a total charge of $184.12 but $116.50 is from base fees!

@Samuel Metcalf- thanks   1) I would recomend getting a HELOC in place on your primary residence duplex  for  as much as  possible...this should be available for  free or a low  cost and the rate will be variable in the  8-11%  range ...prime rate +  margin of  1-3% ) ...the min payment is in interest only payment on outstanding balance   2)  use the heloc for the  remodeling  costs ...pay it down as  agressively as you can   3) on the  purchase of the investmenet  1 unit -  you are  allowed to put as little as 15%  of the price for your down payment ...the pricing you get for the loan will improve  as your down payment  grows so you might look at  75% /  80%  and  85%  ltv  options 

Is the 50k your total purchase price in the above listed example?

If you need to talk through this in more detail feel free to reach out.

and dump the rest into a brokerage account which holds ETF's invested in essentially total stock market indexes (VTI, VOO etc.).

The deals I all cost less than 100k (total) and have solid cash flow once a tenant is placed.

Download the free Deal Check app and start playing around with numbers and figure out how to analyze a deal.