Jo has presented from the newsroom on Melbourne Cup day for the last couple of years from memory. And it has been presented from the Hobart studios on two weekends so far this year (both times with Katelyn Barry as Rachel has had the weekend off).
Yep. The voiceover used is Pete. I actually prefer the original voiceover used every other time (but I'm probably in the minority on this!).
Yes, Chris regularly presents the sport from the Hobart newsroom in front of a different background image to the usual newsroom one you see above on the weekends (last weekend he was obviously in the Launcston studios as Katelyn was in the newsroom instead). And I think the only time the weather is done from Hobart is when Matt is on otherwise it's from Launceston. It can be harder to tell whether the weather is from Hobart or Launceston but the main difference I notice is when from Hobart the graphics are slightly less washed out.
I actually came across this "behind the scenes" snippet of Matt presenting the weather that he shared last year: https://mobile.twitter.com/mattsnewell/status/577032373105078272/video/1
Plus a screenshot of the standing position:
This was reported on in the Examiner earlier in the year. No mention of when exactly it was to take place.
There's also this shot of the Launnie studio I came across some time ago: