A large part of Moore's bibliography, including some of his most praised
titles, is based around him putting a warts and all twist on the
creations of other folks, a pattern of storytelling he began following
long before he worked on Lost Girls. 

Watchmen incorporated characters who originally were to have belonged to
the defunct Charlton Comics.  DC, which had obtained the rights for
those characters, requested that Moore not use those specific heroes as
the company had its own plans for them. Moore's final incarnation of the
Watchmen were altered, renamed and merely based on the Charlton crime
fighters, with certain differences. I doubt Moore was concerned about
whether or not the work for hire creators or their estates were
restituted by the Charlton - DC transaction. 

He also revived the DC comics Swamp Thing series, a moody superior
fright comic from the 70's that was resurrected in the 80's. Moore's
distinct writing and perverse, limitless imagination recharged the new
series, helping it achieve critical acclaim, good sales and controversy.
His work for hire stint on Swamp Thing made him famous. I wonder if
Moore went out of his way to ensure that original creators from the
previous decade were restituted while he toyed with the results of their
work for hire labor?

The primary, secondary and background characters in Moore's on going
League of Extraordinary Gentlemen universe were originally the creations
of dozens of other authors. I suspect Moore didn't pay off the estates
of those scribes after assembling that League. In fact, some claim that
one of the villains who escalated the action in the first mini-series
was "Sax Rohmer's" yellow peril creation, Doctor Fu Manchu. However the
character could not be named in the comic because of copyright issues
that Moore and co. never resolved and had to be known, in the actual
story, as the Doctor or the Lord of Limehouse. 

Prior to Watchment, Moore worked for several comic book companies,
including 2000 AD, where work for hire may have been the standard. His
Marvelman / Miracle Man, for British comics, was based on a vintage
character who may have been a rip off the US hero, Captain Marvel (who
himself owed a big red cheese of a dept to the even more vintage
Superman).

With several years of paid experience working for different comic book
companies prior to Watchmen, Moore should have been unsurprised by DC. 

I'm sympathetic to the plight of work for hire talent and have plenty of
admiration for Moore's formidable storytelling but he can be accused of
practicing what he is preaching against.

Jeff

re - 

Who Watches the Watchmen’s Watchers? 
Alan Moore is angry about DC Comics’ Watchmen prequels.
He’s right.
By Noah Berlatsky| 
Before Watchmen.DC Comics. 
Even by the wretched standards of the entertainment industry, superhero
comics are known for their dreadful labor practices. Jerry Siegel and
Joe Shuster, the creators of Superman, famously sold the rights to the
character to DC Comics for $130, and spent the latter part of their
lives, and virtually all their money, fighting unsuccessfully to regain
control of him. Similarly, Jack Kirby, the artist who co-created almost
the entire roster of Marvel characters, was systematically stiffed by
the company whose fortunes he made. Though most of the heroes in the
Avengers film were Kirby creations, for example, his estate
won’t receive a dime of the film’s $1 billion (and
counting) in box office earnings. In keeping with this depressing
tradition, DC will, next week, begin releasing new comics based on
Watchmen, Alan Moore and Dave Gibbon's seminal 1986-87 series. Before
Watchmen will include not one, not two, but seven new limited series,
written and drawn by some of DC's most popular creators, including Brian
Azzarello, Darwyn Cooke, Amanda Conner, and Joe Kubert. Watchmen
demonstrated to a mainstream audience that comics could be art, and
became one of the most popular and critically acclaimed comics of the
last 25 years.