Can we be allowed taking pictures using dslr cam or phone when on top?

Yes you can

Yes as many as time allows depending on the queue

Yes you can and they even will take you pic with their cams and yours

Yes. Cameras and selfie sticks are allowed. There are photographers, too.

Yes you can, also you purchase your picture by them

Yes you are. There are photographers and there are the tower cameras same as in any amusement park and you can use your cameras as everyone else. There might be lines to turns for the observatories

Yes, the attendants will also help you take pictures 👍

Yes

Sure