I am unsure at the time of this writing, and I've been friends with Milky before Milky was Milky. Apparently, though, another friend was like rewatching the first season and saw this pony:
(yes, the bubble is already burst)
and brought it up with her and apparently, no, Milky was made in a vacuum and she wasn't aware of this pony, at least consciously. I don't know where that comes from, though, the thought that Milky Way was based off of another. Are you referencing Creamy White? Because last I remember, Creamy White's blog came into being before Milky's did, but I know that Milky was come up with before Creamy's blog came about. It was actually a topic some weeks back between Milky herself and Snow, who made Creamy. Teal Deer, as far as I'm aware, Milky isn't based on another pony.