Reverse = Flip face up.
It's worded as written for OCG which is why it doesn't say "Flip face up" or whatever the TCG says.
That's all there is to the Dragon. Since it's a special summon it leaves your Normal summon open for something like Hell Kaiser Dragon. You should be able to figure out the combos for that on your own.
I would assume 'Reveal' means reveal from your hand.
I'll double check on Tethys whether it's draw phase or whenever you draw.
EDIT: Tethy is indeed draw phase. So no double chaining with combo cards for mass draw.