I'm long term bullish Hawaii real estate and with current rate of inflation, you could do quite well if you held it long term - though I know feeding a property is not ideal. 

Many times the ARV is over inflated using bad comps or the rehab estimate is horrifically low.

A cost segregation is so specialized / specific that I am not sure would be of much benefit if you were to get into the field now(In my opinion).The valuation most cost segregation companies tag to certain items are likely 'inflated' to benefit taxpayers.Therefore, I don't think you would learn much about assessing properties or items within a house.I would put your time towards getting the best job out of college(good paying and decent hours) which you can then apply some of the earnings towards real estate investing.Best of luck.

He has $100,000-$150,000 in the bank that is ready to be invested, rather than get eaten up by inflation.

*Used to be 25 cents, but due to inflation...

Regular plumbers will be doing retail jobs so will not be interested in the business usually unless an inflated price.For bids DO NOT tell other plumbing companies what the bid came in at etc.

I am apprehensive about teaming with someone I don't know because I need to be able to trust them not to inflate rehab costs, etc.

Money loses value when it’s not invested due to inflation, rising home costs, etc.

Did the seller give a bunch of free rent or other concessions just to fill the place up at inflated rents thereby puffing the numbers??

The local market data available in your spreadsheet is interesting but it would be much more useful if you broke down pricing by type of rental unitHousing size: #bedrooms, #baths, sqftHousing type: SFR, duplex, triplex, 4plex, >4units in complexIf that data was available, it would be a lot easier to determine what asking price I should list units for.My best current method is1. last years rent + inflation,2.compared with HUD housing data which tells me the 40th percentile rent for the number of beds and baths, by county.