Thanks, I can now try to follow up and see where she got it from. Since I do not own the book, could you also let me know if she gives any reference for this (to any of the 140 sanskrit sources in her bibliography :-) As an aside, Indian books are not necessarily better about the meanings of Indian names: in fact, for very old names like this people with an in depth knowledge of the old language of the vedas, Indian or not, are more likely to provide a clearer etymology. Some of the leading linguists with expertise in that language actually are not Indian, and quite a few of them work in the USA. The name books you find here are not written by them, though, but neither are the ones written in India. The Indian name books are more likely to be correct about more modern (compared to this at least 3000 year old one) names.
The meaning of atri as the devourer is clear, the other meanings as literal meanings I cannot fathom. Atri is a very famous mythological holy man, who, whose wife, and whose descendants appear in many stories. He is also counted as the religious ancestor by many, so myths about his name are likely to be common. One can argue that such meanings are no less correct, just not etymological. How can a folk etymology which the parents, say, believed in when they named their child be incorrect? It would be interesting, though, to know where these meanings originate.
Just for the record, I checked a couple of dictionaries, and none of them show any alternate meaning for either atri or AtreYa/AtreYI, nor do I know of any direct mythological basis for any of the alternate meanings. I will look more and post it here if I find anything.