I work in renovation sales: primarily kitchen and bathroom renovations, so I meet with many individuals who are looking to put their home up for sale in the near future.From my understanding, there is no such thing as a 100% ROI for remodeling. 

If I, as a wholesaler, were to ask a real estate agent to generate a comparable sales statement for me, what's in it for them?

The seller knows this is selling for a deep discount since it's an extremely motivated seller that wants to get rid of the property asap, but needs the money from the sale to move out and would like extra time to move into some place else. 

What type of market analysis do they typically do to determine the sales price?

As a secondary way to find good contractors, speak to contractor sales reps from any local lumber yards.

However when my agent contacted the owner for a viewing the owner says that he has two of the listed triplex for sale and that he wants to sell them together. 150k each and they are probably worth 175k each.So if this property works out it could be a great deal for me so my mind starts working on how i could buy them both.

Just trying to staying liquid for the upcoming clearance sale when the economy tanks.

But really it is little more risk than if I were to build a $600,000 single family home, especially because I live in a metropolitan area with lots of fouplexes (none for sale though unfortunately, because people hold on to them because they are money makers here).

Doesn't have pictures of the unfinished basement but you could finish the basement and have a small second unit: https://www.edinarealty.com/homes-for-sale/915-highview-loop-se-pine-city-mn-55063-5012713#/

Upon sale, you will have to pay tax on the 1250 gain (depreciation) regardless of whether deducted it or not.