I have seen to many people try to do taxes themselves and then we have to go back 3 years and amend the returns because the taxpayer either is exposing themselves to audit risk or missed out on a great deduction that would have resulted in a larger refund 

In my view, tax benefits are almost negligible ($10,000 max annual deductible), the tax on capital gain in $2.8 million would be around $850,000 (federal + state tax), total profit is -$1,350,000. 

There is a fairly new 20% pass through deduction you may qualify for that could help you, but not everyone qualifies.

(we once paid $1800 to a big name plumber in town to replace 6in of plastic drainpipe under a stand alone tub). 3) We need better understanding of the legal structure (LLC) that we should have in place for our property, and also a tax advisor (CPA) to help with understanding deductions.

Insurance would cover it, I would pay the deductible, and no assets would be lost.If you are in an area like San Diego where people are more likely to sue, a judge is more likely to find you guilty, and the payout is likely to be higher, then you may consider an umbrella insurance policy.

It does not create any new basis or new deductions.

You cannot deduct what you did not pay.

For newly constructed, purchased or renovated properties and also retroactive generally over the last 10 years, building components are properly classified into individual units of property and accurate recovery periods for computing depreciation deductions.

.- If I deduct the depreciation for tax purposes, I can't add the flooring cost as an improvement to the cost basis when I sell the property down the road correct?

Deduct property taxes, electric, internet or cable, lawn care, etc.7.