The restricted hours for the Vintage cars is nothing new. Dreamworld have been operating them with "weekend only" availability during off-peak periods for a couple of years now, this has been discussed numerous times over previously on here: http://www.parkz.com.au/forums/topic/6239-dreamworld-ride-opening-hours/?do=findComment&comment=87827 As for the Giant Drop, I'd have to see further proof of this as from what I can see, other than the Vintage cars, there is nothing on the official website or their FB page to indicate that their thrill ride is currently running at restricted hours. They may have just been running a day or two overdue with their maintenance.
Photos for Cyclone have been unavailable since at least the end of January, as that's when we bought our annual passes and we've yet to see them working since then. That said, I'm not exactly sure when they stopped doing them.