Most of the homes I see under 300K are guts or homes that need a lot of repairs.

I got a quote from a waterproofing and foundation repair company for damned near 14.5k and it's quite a shock.

Basically a HML is another way to obtain a loan, just like how you finance your properties with a bank / mortgage broker.Most of them will finance repairs and acquisition.

You say the market’s hot, what about considering:1 taking the bank’s option to Convert to a 30 year fixed term, with maybe piti of $500/ monthly (See if they will lend you 75% of the appraised value OR use the purchase price Plus a detailed list of your costs and repairs) , and then2 selling on contract or lease option at full market price+, ie $119,000 possibly on terms.Look for 10% or more down and finance them as long as your loan is for.This would recoup your initial investment, $12,000+ and costs plus profits And give you passive income of what $200-250+ net monthly?

The floor joints in the basement of the stair were supported by posts and wood headers that had deteriorated and repairs were recommended (reinforce joist connections).

By unbiased, I mean someone who is not employed by a foundation repair company.

If you have a triplex in San Francisco you are way ahead of many people here. 

The profit isn’t there ,the likelihood of losing two years profit in a single repair expense is high ,the potential for a breakin / theft is high and the potential for paying all costs out of pocket when there is a vacancy is high .

I never ever pay above 65% ARV minus repairs.  80% of my leads are free from SEO, and the other 20% comes from referrals, Bank REO's, or Auctions. 

First,  you have a significant jump in value based on repairs but absolutely no budget for repairs.