I would expect at least Kanako would show up in this, since she was a big part in the last Data book, and she is all about getting faith. No way the Moriya shrine would skip out on this.
Besides, I don't think Reimu came up with this plan. When they mentioned the big 3 religions, I imagine Kanako, Namusan, and Miko came up with this, and reimu showed up because she wants more faith for her side.
As for why we didn't get a character shown today... maybe they are just running late? I'll keep looking at the site every so often. I expect to see Kanako, and maybe the Hermit from the manga. As for new or other returning characters, have they comfirmed that? Personally, I would like to see Yuuka in a fighting game, but she wouldn't fit into this getting faith thing. She would just be there because someone hurt her flowers.