@Account Closed That is correct. the 20% is for the 1st year or any portion thereof.
As to your second statement, that is incorrect. "The person," who has a right of redemption includes the prior owner, or any other party with a legal or equitable interest in the property. Additionally, no matter how much time has passed, you cannot take possession until you have foreclosed on the right of redemption (which you can do after one year, or at any time thereafter). Technically, your tax deed may ripen by the passing of 4 years, but again, this isn't automatic. You still have to go through the notice steps and requirements to all interested parties, which is basically the same thing as foreclosing on the right of redemption. After that (or after foreclosing on the right of redemption), you can take possession, but you still will not have marketable title unless you quiet the title to the property, which is a separate legal action.