Yes, Gionee A1 Plus has stereo speaker. One speaker is located on the bottom of the phone and ear-piece also works as speaker and thus you will get excellent stereo sound output.
Yes, Gionee A1 Plus has a 3.5 mm headphone jack.
Thanks to Quick Charging support, it takes just less than 2 hours to fully charge the huge battery of 4550 mAh of Gionee A1 Plus.
Yes, Gionee A1 Plus is made of Aluminium Alloy.