Which themes ? I think it's theme dependent. Soft doesn't work but ayeris mostly does. Apparently for the camera icon you need to rename a file but I've been too lazy to
Winterboard works perfectly fine, also other theming tweak like iconomatic, themeLib, Classic Dock, iWidgets.....
Just make sure that the themes you want to apply are IOS 8 compatible.
Just loaded up winterboard and ayeris. Haven't themed for years. Anyone know where a thread for ayeris is I looked at modmyi but didn't see anything...