Okay, I keep going over it and over it ... and I'm sure I'll change my mind more and more, but ... here's my list as of today...

Harry Blackstone Copperfield Dresden   ...Billy Burke
Bob the Skull...(If we can’t get Jim Butcher to do it) James Marsters
Karrin Murphy...Katee Sackhoff
Michael Carpenter...Dunno.  Still thinking about this one   
Charity Carpenter   Elizabeth Mitchell
Molly Carpenter... Thought I had her, but .... I might agree with Miley Cyrus
Susan Rodriguez...Jessica Alba
The Leannsidhe...Rebecca Romijin
Mab, Queen of Air and Darkness...Helena Bonham Carter
Waldo Butters...DJ Qualls
Douglas Morgan...Dwayne “The Rock” Johnson
Ebenezer McCoy...Fred Dalton Thomas
Thomas Raith...Thomas Bomer
Lara Raith...Haven't figured her out, but I'd like an actual porn star
Bianca...Angelina Jolie
John Marcone...Eric Roberts
Hendricks...Considered Dolph Lungren, but just not right.
Sonya...Michael Dorn
Arthur Langtry...Gary Oldham
Old Capitan Luccio...Kate Mulgrew
Young Captain Luccio...Jennifer Morrison
Mac...Bruce Willis

I agree with most of this cast But I have to admit that the first thought I had at seeing the name Billy Burke as Harry was this Billie Burke which made me laugh.
 

I always picture a young James Cromwell (yes I'm old enough to remember seeing James Cromwell at Harry's age).  First of all he's tall enough and he fits the description. To bad he's too old for the role now.   

As for Thomas Raith I picture either Tom Hiddleston or James Marsters.  Both could easily pull off the role.
For Michael Carpenter I think Liev Schreiber would be a good pick.
Dolf Lundgren is a good choice for Hendricks but I can just as easily picture him as Kincaid AKA Hellhound.
I think that Angelina Jolie would make a better Lara Raith than Bianca in my opinion
And as for Bianca I'd say she should be the one played by an actual porn star.