There is no set combat level to register at the duel arena, but I highly recommend a higher level to have a chance to win.
They are level 124.
no
Level 126 combat in free to play and level 138 combat for members.
Depends on your combat level
88 and 93.
I would have to say combat level 89 or 77
yes
A bronze dragon's combat level is 124.
Some options include magic combat (which is now much cheaper than it used to be), doing high alchemy, and training in the Mage Training Arena.
they are lvl 103
go to combat or levels menu
your combat can but the rest of your skills can't.