The following is crystal ball gazing. I've got nothing official or unofficial. All of this info is freely available to any QF driver who can read their emails and do their maths.
That was 170 to operate the first 8 787s. Given retirements, expansion of flying hours on the 737 and A330 fleets the actual number required by the time the first 8 787s arrive is likely to be closer to 250... or more. Heck, we'd taken 72 on the A330 before our first S/O started on the 787 so straight up that's 240.
Keep in mind the delivery schedule for all 8 787s has been accelerated so that all 8 arrive by the end of next year. With fixed dates and slots against a number aircraft beyond that- which admittedly QF may choose not to take up- it could be a big few years.
On the downside there are 5 744s due to leave. It only about three aeroplanes worth of capacity due to slow flying the fleet and current tight crewing numbers for the current number of airframes so I wouldn't expect a RIN on the 744 until early- mid 2019 at the earliest depending on where the current crew choose to jump to in the interim.
The situation IMO is extremely fluid to say the least. Medical issues and early retirements are running very high. In one week in the last month they lost 4 Captains and one SO. Now il put in one more from left field. If Emerates are pulling out of Syd/Akl/Syd what are the chances they will want to get out of both Melbourne and Brisbane to Auckland? If this was to happen then Qantas would need more aircraft. What's the obvious solution? The 3 RR 747s. Personally, I don't think the company have any idea of retirement numbers, I know of 6 747 Captains who will be gone in the next 12 months, all prior to 60. They are not prepared for this. All in all IMO the next few years will see massive recruitment and training in Qantas. I hope time proves me correct!!!