I doubt that Hannah had that kind of outside help to begin with, also I have the feeling that she willingly took up the coin as a power play. Yes, Harry picked up the coin willingly, but in order to save little Harry [yeah, I know he could have done it differently,] not to gain power.
More likely she took up the coin to have a home again after Harry took out her old one.
Maybe she could have, or maybe she was lying to Harry. He admits picking up the Coin because of the power, she may have been playing to that.
She's be a poor temptress if her first lure blatantly had a hook sticking out of it, Harry lays out that she's trying to get him dependent which means getting him hooked on the no strings attached bits first.
Jim said that Hannah wasn't a wizard because all she could use was fire, but she was very good at it. Lasiel improved on what she was good at, but Hannah didn't display much else. Marcone on the other hand had absolutely no magical talent and Thorned turned him into someone who could use advanced magic that Harry hasn't displayed (teleportation, molecular manipulation)
I should note that Lasciel only had a few weeks to work and get Hannah into Harry-fighting shape (and into the mindset to fry a potentially innocent man, though Harry's abysmal charisma carried the day on that front) while Namshiel had years to make Marcone into an all-rounder.