Sorry, stuck in a meeting...hoping someone else can pitch in...
I can't remember which attribute sets the workgroup on an ACD call. ACD Initiate Processing is the tool step which actually sets the skills and weights and Priority and other settings on the call and kicks off the ACD processing, puts the call on the queue.
A Blind Transfer can be used to send the call to an agent directly, before it goes into ACD processing. Any transfer you do in CustomACDInitiateProcessing is before the call actually enters ACD processing, so the call will not be counted by the ACD and Queue reports.