I'm not convinced. Without mountebank, it would be a good engine board, but here there is Mountebank which makes the engine difficult and almost kills torturer's attack (the draw is still good though).
I'm really not sure about that mercenary. First because you'll gain it a little bit too late (hard to connect urchin and attack), then because the attack doesn't hurt that much in that kind of game.
And I still think a Death cart would be a great help with all the junks from mountebank.
DC can't trash that junk. Do you just mean as a money spiker?
Edit: Edit: Oh, reading the OP again, I see you mean to use DC to rush Duchies and 3 pile with Ruins and Curses.
Looking at the log, this was a Colony game. That makes me think that planning to 3 pile with Duchies isn't that great. Loan helps deal with Coppers decently, and even the slow trashing from TR is OK in a Colony game. You can buy a GH with little issue so your TR makes a little bit of money.
Mountebank is OK with engines. Yes opponents can junk you, but you can also slow down opponents and get more time to put your engine together. I think I would open Loan/Silver, aiming to get two Mountebanks and then BCs after that. Depending on the opponent, I would consider Trade Route (followed at some point by Great Hall) and Urchin. Note that Urchin is not so hard to activate if you have a couple of MBs. Hmm, maybe Torturer instead of a second MB would be good, just for the added draw. The goal is to get rid of Coppers (and maybe Estates) fairly quickly and get into Colony-buying mode. Haggler at some point would be nice, just to gain Platinum from a Colony buy.