You can incorporate flower petals within the mixture, but this can make the mixture more difficult to hold together in balls, so don't overdoo it.
Use tiny cup cake moulds or other shaped moulds to make shapes rather than balls.
Beginners will usually find Granular Citric Acid easier to use. To improve the look and texture of the bath truffle you can use Powdered Citric Acid.
If you choose to use cocoa butter, the harder nature of this butter will mean that the truffles themselves will become slightly harder and because it's less 'sticky' it may not take petals so well, but they are easier to pack, as they will not 'melt' at such a low temperature and possibly spoil any packaging.