ugh this is one of my pet peeves, as there isn't a thing on this planet that can't be written without someone having thought of it first. specially if i write a letter "a" or use the word "the" first in a title, and especially with sexual conotations as good pornographic writers seem to just disappear without any notice so stories wind up like "The Lady or The Tiger" where you have to make your assuptions and hope that leads to some specualtion of what type of person you are.
i've found in my experiece that if there is a disclaimer as to where you found the publication(story) who the original author was, and probably a few other particulars like when, some of thier character names, or where, then you might not be nailed for plagerism as credit for the whole idea is given to the originator
of course this opens up a whole can of trouble as where does one in a court of law draw the line between an author's idea and adding on to an existing one.
in my opinion and i stress the word opinion
make a discliamer and give credit of whom the original idea came from and that names are changed to protect his copyright rights as well as yours. try to change as much as possible since i dont' really know what percentage a person can change something from an existing product to make their own original idea, and yes there is a small percentage you can change of an existing product to gain credit for your new improved version or your brand new version.
check other media for examples, like movies, song remakes, similar products with almost similar logos.
sounds like a lot of trouble, but in the end, your just protecting your story, even though the idea came from somewhere elsel good luck.
all in all i look forward to some new input to old stories, specially since a lot of them just seem to stop like there is an upcoming chapter but none never show.
besides i'm pretty sure that if you do some digging on this site, you'll find that almost all of them have the same idea so it's pretty hard to get nailed for plagerism, specially since only so many peoples names can be used without doubling up, look up any of the female names and i bet theres plenty of stories with that name being used in the same role.
hope to read more
Robert