My theory at this point is that Stirling's goal with the Emberverse is to develop the ultimate Swashbuckling Adventure setting, where he can mash up whatever cultures and literary characters he feels like. Hence we get odd pockets of survivors who have painstakingly reconstructed Anglo-Saxon Britain or whatnot.
-- the author has stated several times on facebook and elsewhere that the Emberverse is "my Hyborian Age", which seems fair enough.
The Peshawar Lancers is of course an open and affectionate homage to the exuberant adventure fiction of the classic pulp "Oriental Adventure" stories, from Harold Lamb and Talbot Mundy on down, with a nod to Kipling along the way, especially to
Kim. (He did an introduction to a volume of the University of Nebraska Press collection of Lamb's Cossack stories.) I'd say there's influence from Sienkiewicz et. al. too.
With the caveat that Howard was attempting to put "genuine" medieval Europeans, Renaissance-era Turks, ancient Egyptians, quasi-Iroquois Picts and so forth all in the same setting; which is sorta cool, and not altogether different from what Tolkien did with Middle Earth; where you have Anglo-Gothic Rohirrim, 19th-century English yokel Hobbits, late-medieval-European Gondor, and Saracenic "Corsairs of Umbar" plus Treasure-Island style primitive Woodwoses, and many more.
What the Emberverse does is put "reconstructed" versions of past cultures in the same setting; the descendants of SCA types "living the LARP" meeting neo-samurai whose ancestors were demented Japanese nationalist reactionaries and so forth and so on. Cowboys and Romans and pirates, oh my! In other words, they're not fake past cultures trying pass as real (fictional) ones, they're -actually fake- recreations of past cultures, themselves modeled in part on historical/fantasy fiction. A bit recursive, but fun.
Just as
The Sky People and
In the Courts of the Crimson Kings are a homage to "planetary romance" by Burroughs, Brackett and so forth. Christ, Leigh Brackett
appears as a character in the prologue to Crimson Kings, which is like,
a hint, one would think.
This seems to get some people's goat; God alone knows why, and God knows there's enough fiction of different types out there to suit anyone's taste.