Yes, BlackBerry KEY2 does have the OTG support.
BlackBerry KEY2 is available in 2 variants - Single sim and Dual Sim. The model available on OnlyMobiles.com is a dual sim variant. It has a hybrid sim slot. You can use either 2 sim cards or 1 sim card and a memory card.
Yes. Though BlackBerry KEY2 does not have the LED flash for the front camera, it does have the Selfie Flash using LCD display.
Yes, BlackBerry KEY2 does have the NFC support.
Yes, BlackBerry KEY2 does have the LED notification light. You can even program it as per your requirement.
Stellar battery life. A tactile and genuinely useful keyboard. Great software with a focus on security and privacy. What more could you want? The BlackBerry Key2 is an exceptional phone.
The BlackBerry KEY2 is the best Android-powered BlackBerry ever made, and it improves on last year's formula in almost every way.