CAPITAL GAIN TAX

1. The new amendment will take effect only from 01.04.2020 and there is no specific explanation about the sale of two residential house property. 
2. In your case, if you have sold two residential house property and sale proceeds are allowed to be invested only in one residential property whether constructed or purchased within the stipulated years. 
3. With respect to investment in sec 54EC, it will be allowed to be invested only one time in an FY and restricted to one residential house property. 
4. The option available to you is (4), where property 1 can be sold in a year and sale proceeds can be invested up to Rs. 50 lakhs in Sec 54EC bond and another year property 2 can be sold and invested in sec 54EC bond up to Rs. 50 lakhs. However, you should be careful in while making the investment to make sure that investment does not fall in the same FY. 
Please correct me if the above solution has an alternative view.