I checked INE (the Spanish statistical site) which Frollein
Gladys should've done and it is indeed used as a first name, though it seems to be more often, if not, exclusively used on females.
Rene is right with regards to Huertas falling in fashion as the data on INE indicates.
Here's the source:
http://www.ine.es/dyngs/INEbase/en/operacion.htm?c=Estadistica_C&cid=1254736177009&menu=resultados&idp=1254734710990
By the way, what source did you use for this following statement:
"This was the name of a Muslim converted to Catholicism. As he was given a fertile plot of land he chose this name to be known."
I can't seem to find a source for it so far.
My PNL:
http://www.behindthename.com/pnl/149249My blog:
https://maybeitisdaijirou.wordpress.com