And can you repeat the process with future properties?

@Jeff ObertsI have an extensive detailed checklist that winds up repeating itself for each similar room.

This could mean different things to different people and I think certain factors affect whether or not something is a good deal or not, experience (a good deal for a newbie is different to seasoned investor), location ( a good deal in California could be a horrible deal in Indiana), strategy ( a deal could be bad for a flip, but really good for a rental), skillset ( someone who is handy can save more money on labor opposed to someone that doesn't know anything about handy work, also someone that can manage properties opposed to someone who isn't cut out for it, etc).

how will it affect multi family properties?

How To Invest In Real Estate is a good general overviewThe Book On Investing With No (And Low) Money Down has good information on the different ways to fund investmentsBuy, Rehab, Rent, Refinance, Repeat covers the BRRRR method that is talked about in just about every podcastLong Distance Real Estate Investing teaches you how to invest when you're not in the same market.

I don't have apartments (yet), but both of the problems you mention (noise, odors) potentially affect plexes also.  

My focus is to get as many cards and make as many calls as I need to build a quality team of fellow investors, contractors, re agents, etc.I do tend to repeat myself! 

You simply stand still in a relaxed position with arms down ,legs about shoulder wide and allow dozens of strangers for a line .have them run up and kick you in the gonads repeatedly over and over ....

The amount of equity you have in a single family home will also affect the rate as well. 

After materials, some consideration to where the current hot water is located and the age of the piping it's connected to will affect the price.