I haven't read all the comments, but unless you NEED the money, I wouldn't sell anything. You can always find uses for the other speakers, a fill, or second system. In my area we do a number of three system weddings and I kick myself for selling some EVs when I thought I needed money.
BUT if you do have to sell them, I would try your local Craigslist first. I am not a huge Alto fan and I don't know anything about the Eon's, but selling locally, getting CASH in hand and not having to ship, is well worth it. Sometimes, a music store will let you put up for sales, I would also e-mail a list to every local DJ, band, agent, venue you know and hopefully that will work.
The cost of shipping will kill most hopes of selling. Your speakers are not that great, sorry, and so the price that you will get for them, added with the shipping, to most, just wont be worth it I think. I could be wrong.
The last thing to remember is that you can't get crap for used gear, no matter how clean it is, no matter how few times they have been used, they are still used.
My 2cents.