In CA, tenants are considered in possession of the unit until they turn in the keys, so you should not have to refund any $$. 

I hope to utilize the skills that I possess while continuously building upon what I know to become a successful full time investor within the next three years.

The only way to "cure" a void tax sale is to adversely possess the property for three years after you obtain your tax deed.

My parents did 1 in Singapore, made over $100,000 within a year and did not even have possession of it, and so did 1 of my former classmates. 

To clear up a few misperceptions in this thread:You can take possession as soon as you have your certificateMany tenants will sign a lease with a 30-day cancellation clause in exchange for below market rents or security deposit concessionsIf the property contains a residential structure, a redeeming party must pay you for the VALUE (not the cost, which is usually much less than value) of the repairsAlmost all lienholders must redeem before exercising their own rights to take the property such as foreclosureLocal government liens (weed abatement, demolition, sewer, etc.) do not have to redeem before foreclosing but they must reimburse you for taxes.

We have:1) The best weather year around2) We have some of the most beautiful beaches minutes away3) We speak the language (English)4) Puerto Rico is not a foreign country. 5) US Dollars = US Possession 6) We live were people vacation (Tourist loves PR)7) Buyers Market with thousands of properties under Market value8)............There's so much to say, but here's a lil of data for those that don't know. 

If none of the above it could be a perfect Adverse Possession opportunity even if you have to pay back taxes. 

It take just a little over a month to evict someone, and if they are not paying rent, it's very easy to get possession of the house and a judgement.  

See if you can take possession of the homes that are being foreclosed upon.

Civil Code Section 1950.5(b) specifies what can be deducted.If the tenant waives the right to documentation receipts are not required.No later than 21 days after regaining possession, the appropriate security deposit amount should be returned.I give the tenants an option to do a pre-inspection about 10 days before move out.