Oh well it is actually their own fault and Capcom can't really blame me for their mistake. And somebody else will probably find it out sooner or later anyway so I might as well spoil it now.
http://www.capcom.co.jp/tatsucap/charactor.html
On the new character site only a few character images are shown, but Capcom made the mistake to preload all images in a Javascript function in the HTML source. The images are not uploaded yet, but the image names reveal the new characters, one of which was already announced.
'images/oncharactor_btn_ryu.jpg'
'images/oncharactor_btn_chunli.jpg'
'images/oncharactor_btn_batu.jpg'
'images/oncharactor_btn_alex.jpg'
'images/oncharactor_btn_morigan.jpg'
'images/oncharactor_btn_souki.jpg'
'images/oncharactor_btn_veautifu.jpg'
'images/oncharactor_btn_zero.jpg'
'images/oncharactor_btn_frank.jpg'
'images/oncharactor_btn_ken.jpg'
'images/oncharactor_btn_chas.jpg'
'images/oncharactor_btn_tekka.jpg'
'images/oncharactor_btn_yatter01.jpg'
'images/oncharactor_btn_doronjo.jpg'
'images/oncharactor_btn_karasu.jpg'
'images/oncharactor_btn_yatter02.jpg'
'images/oncharactor_btn_joe.jpg'
'images/oncharactor_btn_tekkabla.jpg'
'images/oncharactor_btn_roll.gif'
'images/oncharactor_btn_rock.gif'
'images/oncharactor_btn_ptx.gif'
'images/oncharactor_btn_saki.gif'
'images/oncharactor_btn_gold.gif'
'images/oncharactor_btn_jun.gif'
'images/oncharactor_btn_ippatu.gif'
'images/oncharactor_btn_polimer.gif'
Mega Man Zero (or Zero Gouki)
Frank West
Yatterman #2
Joe Asakura
Tekkaman Blade
That's it :)