Yes, Nokia 3310 does have slot for 3.5 mm music jack.
June 2017 - first week.
No. Nokia 3310 supports only 2G network. So, you cannot use only 4g sim card - Jio sim in this phone.
Yes, Nokia 3310 does have LED flash placed just near to camera.
There are a few things that do bring back the feeling of owning an original Nokia 3310, such as the classic Nokia ringtone, the physical buttons, the tiny body, and solid build quality.
You can buy other feature phones for less than this, and the new Nokia 3310 doesn't justify the extra outlay over the simple nostalgia card it's playing.