Here is an update on the sleep issue with my Intel Mini after upgrading to Remote Buddy 1.1:

Things have improved - I can now put the Mini to sleep manually (via the apple menu) with RB running and the Wiimote connected. I can also get the mini to sleep automatically on the timer provided I disconnect the Wiimote from the RB menu. However, the Mini will wake itself back up if it tries to sleep automatically (timer) if the Wiimote is connected.

So for now, my workaround is to simply set the hardware prefs for the Wiimote to disconnect due to inactivity 1 minute before the mini is scheduled to sleep...