Yes, JioPhone is a dual sim mobile phone. You can use one 4G sim card and one 2G sim card.
JioPhone has 2.4 Inch QVGA TFT screen display. It has about 167 PPI ratio.
Yes, Jio Music App will be inbuilt available in JioPhone.
Yes, You can type in Malayalam language in JioPhone. JioPhone supports 22 Indian vernacular languges.