Yes, You can use Sony MBH20 with Nokia 3310.
Just about 8 grams.
Sony MBH20 has average talk time of up to 8 hours. So, you can use it for almost 2 days talk time.
Yes, you can.
No. Sony MBH20 do not have volume control button. You cannot increase or decrease call volume but you can use your mobile phone's call volume control button for the same.