No. You cannot record calls in Nokia 3310.
Yes, you can set MP3 ringtones of your choice.
No. You cannot use Jio sim in Nokia 3310.
Yes, Nokia 3310 does have calendar.
Yes, Nokia 3310 does have slot for 3.5 mm music jack.
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.