So I just got this book called Rituals and Spells of Santeria by Migene Gonzalez-Wippler and it talks about all the intiations and such in good detail(nothing secret was told of course). Well when it came to talking about Omiero it said that in it's preparations it is made only by Santeras and as they're doing the process the Santeras sing the ritualistic chants of each Orisha in the original Yoruba. So this makes me think now about the Elekes don't they usually need to be re-fed with Omiero sometimes?? From what i've seen so far online you can't purchase Omiero, and i'm guessing you can't buy it in Botanicas?? Just makes me think if ones Madrina and Padrino live far away how much of a pain in the ass it must be to get the Omiero, that being said can the Elekes be fed with something other than Omiero?
Wippler books are only good for one thing: lining the kitty litter box.
This isn't because of the content, she usually gives decent or accurate information, but it's because of how she came to her manuscripts in the first place. She's shady and only goes after the "idiot market" - if you want to learn more about omiero, simply ask your godparent. But also, Wippler does publish some info that most people would consider profane...but hey, so do some of the more honorable authors and scholars too.
And to answer your question about elekes, no. To be washed in omiero is not the same as a feeding. Elekes get washed once, and fed once.
Finally, don't fret over omiero. Ab'orisha rarely need any in their possession or home. If you do, your godparent will direct you as to what is appropriate for your situation.