Firstly IMO the name Atris really comes from the latin adverb "atrum"(dark, sinister, etc.). i always look up names that occur in computer games and in most cases one can find a latin, greek or any other root that fits. thats because making up good names is quite hard. so they often use other languages to do it. and they never care about gramatics... why should they.
Secondly: here comes my theory...
Until now you all only mentioned two female jedi. But in fact we have seen three: the white haired one from the conseptional arts, the one wearing the white robe and hood AND the old evil female jedi with the dark hood, the one with the white plaits. could SHE be Atris? if she was Atris the name would fit wouldn't it? (only a thought: than the one from the conseptional art could be bastila. if you look closely it might really be her... only problem: i can't imagine how she might have aged that fast!
and now go on.. tear my theory into pieces!
(i must admit that it is really strange they just removed the post saying the white haired one was Atris. they never said it was wrong... they would have if it realy were wouldn't they? but still... there are two female jedi with white hair... some one might have mixed something up!)