ORCABROWSER is "only" a new GUI for the Gecko. Folders, Data, handling etc.. is the same as on FireFox.
AVANTBROWSER is the same, based on the IE. You can use AVANT on nearly any IE-Version. It works on IE5 just as it works on IE9.
it should be not very diffucult to add ORCA support to CC.
greetings,
#k.