I'm having a lot of trouble deciding what material to use (pressure treated wood vs composite, etc).

The best way to build rapport is by being on the property fixing things and treating residents in a friendly and polite way in all interactions.

The reason I still consider them a scam is because they never meet in person with the person paying the fee, the person can say they have whatever condition they want that qualifies them for the ESA, and it seems like the main purpose of these sites is not to evaluate or treat that condition but rather to just document it so the site can generate the certificate and collect the fee. 

. $19,500 or $26,000 if you are 50 or older) you can't make any additional employee contributions to the Solo 401k.  2) While employer contributions made to your day job plan are typically not aggregated for purposes of determining the amount of employer contributions that you can make to your Solo 401k, 403b plans are an exception to the general multiple employer rule: for purpose of plan contribution limits, you would be treated as if you are participating in one employer’s retirement plan, which limits your aggregate contributions to both plans to $57,000 plus a catch-up contribution of $6,500 (if you are 50 or older). 

The lender already said she doesn't care about reimbursing me directly, since she wasn't going to be able to close it in time for next week.I'm treating this first real, deep rehab as a learning experience... sure I want to make $ from it, but as long as I make SOME money from it, I'm going to learn a helluva lot during it.

If I were in your shoes, I would essentially treat it like having a roommate.  

My question is, if I were to pull together several residential properties into a portfolio could they be treated by a lender as a commercial property where I'm better rewarded for decreasing expenses and increasing revenue?

You have a few things going on here, @Huy Thai.The first issue is that those structural members are probably pressure-treated lumber.

Above $150k, this allowance is phased out and the net rental real estate loss is suspended and carried forward to your next tax year.If you or a spouse are a real estate professional, there may be opportunity to treat the rental real estate losses as non-passive.Regardless, in general rental real estate losses will not be able to offset your self-employment income for purposes of the self-employment tax, and that will be the biggest tax for a completely self-employed individual.If you have the scale to absorb the cost, a good tax advisor is something you might consider adding to your team.

It is a fun business if you treat it like a business and have set yourself up so you have a mindset that tells you that you will handle all problems with business logic and never allow a tenant to get you upset or emotional.