Yes, Gionee A1 Plus does support OTG.
Gionee A1 Plus is available in 2 colors - Black & Mocha Gold.
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.
Gionee A1 Plus has dual sim card slot of different size. You can use one micro sized sim card and another nano size sim card in this phone.