Wow, Mushroom Bridge looks great! Glad they kept the bridge rail boosts, bomb cars, and mushroom cars. Hope the Wiggler cars are there too.
I think this solidifies our final 3 GCN tracks: Mushroom Bridge, Daisy Cruiser, DK Mountain. All got high quality recent Tour remakes, all are fan favorites, and they're all distinct from each other.
Like some others here, I'm now thinking that Wave 5 will have two GCN tracks. Mushroom Bridge and Daisy Cruiser both seem like locks for the BCP, yet neither seem like "grand finale" Wave 6 tracks. So, I think the final 7 retros will play out like this:
Wave 5: Mushroom Bridge, Daisy Cruiser, Koopa Cape, Sunset Wilds
Wave 6: Bowser Castle 3, DK Jungle, Rainbow Road
I also very much think that Piranha Plant Cove WON'T be the "new" track for Wave 5. I'm not sure why that's becoming a prevalent theory. Nintendo has shown that they like to have a brand new track in that slot whenever possible. MobDK and MobBR will probably be debuting this summer, which is also when Wave 5 will probably be coming out. Either of those make a lot more sense than PPC to me.
Then that would leave PPC and whichever of DK/BR remains for Wave 6, as well as one brand new track which would debut first in Wave 6, then in Tour shortly after (like SHS and YI).