I figured out how to add custom colors based on given example at SAPUI5 Explored - Custom colors
About grouping/aggregation problem I have found the same use case and proposed solution in stack overflow. http://stackoverflow.com/questions/24453439/how-to-group-sapui5-odata-before-bind-to-control-at-client-side
which doesn't work at jsBin example but if you import code in your project and adjust service uri.
Regards,
Filip