I do agree with Dan that appraisals are more unpredictable, but would expect this to improve with increased activity & national recognition of ADUs in the lending world.3) Not sure what is meant by stability.

Assuming he actually got the majority of his capital back in each of his 10 or so BRRRRs (which seems to be the case) he's likely accumulated a good amount of equity and is benefiting from debt paydown and tax advantages (with potential appreciation and improved future cash flow once the properties are stabilized being nice-to-haves if they happen).

whats  projected value on home post improvements ? 

Total cost is $3,200.I know the De Minimus safe harbor rule allows you to deduct anything under $2,500 and that anything over this amount, if considered a capital improvement, would need to be capitalized and depreciated over a certain period of time (the life expectancy of the improvement).

If the property needs capital improvements and as it stands is worth over 125k I could see a lender potentially issuing a rehab holdback against the ARV..

There are a few things to consider as a host to improve the listing and maximizing revenue.

For example, I broke down and bought a forms package for $1,000 that saved me so much time and improved my company, particularly as I brought on employees.

Either the rates improve and it can cash flow with a long term mortgage or I can sell it when the market improves (I feel like both will happen at the same time). 

STR regulations are a big consideration before you make any big capital improvements specifically for short term stays, also running your numbers and making sure that your area offers consistent returns above what you'd get renting it long-term.

Added cheap square footage and improved features - ie. additional bedrooms, quality outside space, and upgrades throughout