Brushing damages the hair shaft so it's not recommended. That being said, I do brush mine daily with a soft, vinyl bristled brush for bathing horses. It removes the surface dust and debri and (to my untrained eye) does not appear to compromise the hair quality.
When they're heavy in fleece, I switch over to pelletized hay and alfalfa, which really cuts down on the debri that gets embedded and that cannot be removed by soft bristle brushing. Also, we do not turn our Angoras out to free browse unless we're there to supervise. They have a nice grassy yard with ample space and play areas to keep them happy and occupied and that's where they stay.
Some folks cloak their Angoras to keep the fleece clean. But that's not an option here in the desert. It's too hot for that.
As far as doo butt goes, I keep the hair back there clipped back away from the anus and natural flow area if you know what I mean. When it does get soiled, I rinse it off with the hose using baby shampoo or Basic H if need be. I suppose you could shave back there, too.
Geneva's a pretty name for a pretty girl.