ADL-KGI-PER, you gotta be kidding. Even Skypest couldn't ops on PER-KGI-MEL.
NXB,C,F are heading to Hawaii as they were
A) The first off the production line with the exception of C (NXF 55001, B 55002, C 55151) and also the 1st 3 for Impulse
B) Higher leasing cost
C) Hawaiian were desperate for extra 717's
D) The contract for those aircraft had ended
As for extra aircraft. That has been floating around for yonks. SYD-CBR-MEL vv sectors, 717's on blue tail contracts etc etc, heard it all before. Until it happens (ie you see it in flesh) you don't believe anything that comes out of Cobham.
Air Tran have parked up 14 of their 717's so who knows what will happen.
But to Answer your Question about Engineering
PER is major base for B717's and BAe 146
ADL is heavy maint base for all aircraft and line maint for 146
BME is DHC-8 only
DRW is DHC-8 and minor 717
CNS is DHC-8 and minor 717
ASP is T/A's only
MEL 727-146 T/A
SYD 727-146 T/A (used to do 727)
BNE 727-146 T/A (used to do 727)