Until you become an expert at rehab costs, one investor told me a "quick and dirty" way is estimate $20-45 per square foot depending on condition (20 - light cosmetic stuff, some flooring etc.. 45 - trashed - full gut.)

@Kenneth LaVoie is an expert on building efficiency and has taken advantage of Efficiency Maine's numerous rebate programs to keep the winter out of his multifamily units.I personally have separated all the heating systems in my units, mostly with Rinnais, but you can get away with that in the Midcoast more so than other Maine towns where the expectation is that heat will be included in the rent.

Should I expect to pay a tax expert to give me a more accurate sense of my situation? 

To ask an experts like yourself.

Also you don't know what you don't know so if you don't have a thorough understanding of where to look for new housing laws and restrictions that maybe a bigger liability than paying an expert.

I recommend you become an expert on those markets, down to the submarket and even block level.

I want to know how a pragmatic, numbers-driven investor can gain expertise, or find experts, to turn around my property evaluations and offers in days, not weeks.

In my local market, I've seen movement of people from the suburbs back into the city as well.Keep in mind some of that "stupid money" is from institutional investors and private equity firms with full time acquisition analysts and market experts (not newbies like here on BP).

I know that's not a ton for some of the folks on here but I was no expert at talking to people either. 

As the expert, most of the real estate duties will be yours, but many times the capital partner will have some regular minor duties as well.