I don't remember Namshiel reaction to Harry using soulfire
Yes, Jim may see Marcone as grey, which probably happens to us too, I think the better part of Marcone is not his love for children but the fact that he would risk his own life to protect the city, as we seen in PT/BG. But I also think there is truth in his Even Hand statement about him being a monster. He has chosen to do evil things for the love of power. That is quite evil, right?
I also think he will be worse due to Namshiel but I still think that Harry will prevent him for losing his soul. I don't know if Marcone will survive the BAT, but I think his soul may be redeemed, of course, probably with the standard sacrificing for the greater good.