Yeah Taming the Flames is a L6 in House K, as default there are 50+ fire elements and mephits. Also the fire elementals respawn at the lava jets all the time. In one run of the quest I got over 20 White coins. It's a free quest as well, and as long as you have decent fire resist and a nice cold based weapon can finish them all off easily.
I think the person who kills the enemy is the only only one that gets the coin, so I reconmend solo runs to maximize the chance. Also the level Norm, Hard or Elite affects the drops.
As for rewards not sure, but know you get recipes. Which when combined can assign a Icy Burst status to any weapon. You have to get 3 recipes, as it gets cold touch->frost->Icy Burst level of change.
Also think there are white, blue and purple coins. Like the last event, so I guess the purple ones have a higher chance of the better stuff? You need 20 white? coins to hire the skates if you want to try the jumps in the harbour.
Look at this video
or
I have abundant step, so fingers crossed.
Also a list of all the recipes and rewards it seems. Still need ingredients, darn. Wish I had kept some things like twigs, I'm sure they'll be increased in price on the AH now