Yes, Samsung Gear Fit2 Pro can be used with any Android or iOS devices with Bluetooth connectivity of 4.2v or higher.
No. Samsung Gear Fit2 Pro does not have the NFC connectivity feature. It has Bluetooth 4.2v.
Yes, Samsung Gear Fit2 Pro does have the count down timer.
Yes, you can receive text and even can respond from the watch with some pre-programmed responses. You can see the call alerts but you will require either Bluetooth headset or the actual phone to talk. There is no speaker or mic in this band.
Yes, Samsung Gear Fit2 Pro does have the heart rate monitor.