Yeah, it can be done. All these activities take around 1 hour each.
I did scuba diving twice in Havelock & it was super fun.
You can check this for some info.
Most definitely.
It is perfect for a honeymoon. You'll love the pristine clear beaches and also a lot of activities that you can do there.
You can refer this for some I sights. There's a video you can check to see how beautiful the islands are.
https://www.tripoto.com/trip/explore-andaman-in-5-days-5d46b3bc2755a