Bollinger would be a better option over McDonald. McDonald isn't even a reliable bat, so it's kind of pointless. Bollinger, Hily, Johnson and Siddle would have made the perfect bowling attack. 2 Left armers, one who is very quick and has a good bouncer and can swing it at times (Johnson) and another that is a great swinger of the ball and bowls at pace (Dougie). Then we have the 2 right armers, one who is also a great swinger of the ball (Hilfy) and one who can cover pace, swing and seam when on form (Siddle).
I can see the selectors point of reasoning tbf. McDonald is a tight and accurate bowler, hitting the cracks and seaming the ball so he would be good on a green top. His accuracy would provide the pressure we will lack with Hauritz not on tour. Hilfy, Dougie, Johnson and Siddle could all go for runs so we do need that stability.
North really is an interesting inclusion, his batting is good at the best of times, and I'm not convinced on his spinners. Whether he can cut it as our number 1 spinner, providing Clarke's fitness will be interesting to watch. I feel McDonald will take up Hauritz role of providing the pressure, and I doubt we will see North much. I expect McDonald to bowl around 30 overs tbh. If Clarke is fit enough to bowl, we could see him bowl 15 or so overs but I don't expect to see North for anything more then 12 overs.