Brighterside no one knows if the +Qatar scheme will be extended into early 2018.
However do look to see if you qualify for STPC on your return. See
The QR STPC (stopover) policy? for details. Whilst you cannot choose your hotel the STPC package includes a visa where required, a meal allowance and hotel transport.
You will get nowhere with QR regarding the relatively minor schedule change. The 12 hour rule (+Qatar) and 8 hour rule (STPC) are based upon your actual scheduled flights, not what was booked. That said the rules for +Qatar appear to be more liberally interpreted than the STPC rules so there is a remote chance that you could get lucky!