-with the standard deduction being so high now, having a loan against your primary may not be the most economical. 

When calculating tax on profit, will We be able to take 500k (married) deduction on the entire house or only for one of the units? 

You should be able to deduct the interest portion of your payments, but even that is not guaranteed.

Since I have already filed my taxes for 2020 a couple months ago would I have to amend the tax return to add in the deduction for the prior year contribution? 

Your math not correct and you are not factoring in the deductions(such as the standard deduction for you).Very simply: If you gift half of the balance to your fiancee (which you can do with the annual exclusion and the lifetime exclusion), with 20k W-2 and let's say 28.5k cap gain ( 32k sale proceeds less 3.5k basis), your cap gain is around $750.

If not, deduct for damages per your state laws.4. 

After a month goes by, deduct the entire water bill from you payment and outline what you are doing.  

I have read that if we sell it under contract we can't deduct depreciation, but what about the repairs we have done over the years?

If we have a STR rental in Florida which we rent from Memorial Day until October, then travel to our STR in Brasil & live there from October until May, would the travel be deductible? 

Also, do you all factor in depreciation and other deductions into your returns?