A cornucopia of tax questions - please help!

[Renee H.]

Hello, a little bit of a long post with a couple of tax questions :-) I'm looking for some help as I've become increasingly confused around taxes!

Crossing my fingers someone could help me find answers to questions that have been bugging me. I’ve begun to grow skeptical of my accountant’s advice (some of her suggestions completely contradict lots of advice I’ve read on this forum), and I was hoping to get someone else’s perspective.

Background: I purchased a duplex in 2019, rented out one unit and occupied another side.

Starting from 01/01/2020 I no longer lived there but continued to do repairs as the unit was not in great shape when I bought it. Most of all the repairs I did myself. In August 2020 I rented out the second unit. Not a real estate professional yet, unfortunately :-(

Questions:

1. 1. Should I add the other unit as a separate asset and take depreciation starting from 01/01/2020 - Date of Conversion (as I moved out in December 2019)?
2. 2. What cost basis should I use? For example I bought the house for 200,000 (40k land included) and was depreciating the unit 1 based on 80k ((200k-40k)/2). But in Jan 2020, the fair market value for the house increased. Should I use the original purchase price as my cost basis or how can I show that the value of the house increased? For example Zillow analysys or a value (rate increase) from the city property tax statement?
3. 3. Can I expense materials the same year as I was doing all the work myself and the majority of work was mostly fixing non-working, absent, hazardous or leaking things (stairs, faucets, some plumbing/pipes, electrical, non functional door handles, some trim fixing/replacement, painting, blinds) in order to bring the place to rentable condition?
4. 4. Should I expense those materials using bonus depreciation, or the De Minimis Safe Harbor or they can only be capitalized?
5. What qualifies for bonus depreciation deduction and do you always need to do a cost segregation? Do I need to expense each item or material separately? In my case, I just have supplies and tools for repair projects.
6. 5. Would placing LVP be considered as an improvement or I can claim it as a repair when replacing very gross, stained, smelly carpet with holes in it and a rough subfloor (not possible to refinish)? I did all the work myself, just purchased the supplies.
7. 6. A couple of windows had broken jambs and glass and I had to replace them (I tried to restore them and repair the jambs but it didn’t work). Will this be considered a repair (as I didn’t replace all windows, only ones that didn’t function) or improvement? Did the installation myself.
8. 7. How can I allocate tools I bought to do the work? Drill, nail gun, saw, bits, blades, work light, dolly, shop vac. Can I expense them right away or should I capitalize them?
9. 8. Not sure what I should do with a trailer and accessories (hitch, ties, a coupler lock, moving straps) I bought specifically for the rental business to carry supplies? Should I expense it or capitalize? How many years?
10. 9. Is it possible to expense a lawn mower (new), leaf blower (used, purchased on Facebook marketplace) and snow blower (used, purchased on marketplace) or do I need to capitalize them? What method should I use?
11. 10. And just to double check that I found the correct information, I can deduct PMI in addition to my mortgage interest?

Thank you so much for all your answers!