Tax Schedule E Questions for Active Participation Loss

[David Y M.]

Current Situation 

- Trying to tax plan for 2020 tax year

- househacking with SO and 3 other roommates, and planning to claim active participation and claim a deductible passive loss

- Deductible expenses are based off formula Shared Living Space/ Total Living space = 3000/3250 = 92%.

Seems to me it'd be super beneficial to use this to our advantage, and make some improvements on the house since likely we won't be able to take advantage of this tax rule if we get married and our combined income is over the threshold. Is my thinking correct or are there more nuances I am overlooking?

Questions: Would these be allowed for schedule E? I plan to talk to a CPA later but want to at least try on my own first and see what might be able to fly.

- If I own the house and make her pay me $1/month to live at the house is that technically allowed? What would be reasonable since we are not married.

- What expenses are considered okay to not have explicit documentation for such as a receipt? - like for these under $50 home depot runs, supplies/tools that I buy on facebook marketplace/craigslist, or mileage runs that I don't have documentation for. Would IRS consider this okay if the expenses seemed reasonable?

- For the safe harbor/de minimus tax rule of $2,500 --> does this only apply to personal property, or can it apply to contract labor such as painting the outside of the house?