We're back.
Now for the fun part where I explain the above additions since they don't line up perfectly with the above information
@Skipper93653 posted that you should read first. It was later noticed that the gaps between the classic courses were all multiples of 5, and as each course has five of these files we can look at the size of the gaps to determine how many courses should fall between each:
G3ds_WarioShip - Gagb_BowserCastle1 - 1
Gagb_CheepCheepIsland - Gagb_SkyGarden - 3
Gagb_SunsetWilds - Gds_DKPass - 1
Gds_LuigiMansion - Gds_WaluigiPinball - 2
Ggc_DinoDinoJungle - Ggc_YoshiCircuit - 3
Gn64_KoopaTroopaBeach - Gn64_PeachCircuit - 3 *
Gsfc_DonutsPlain2 - Gsfc_GhostValley1 - 1
Gsfc_GhostValley1 - Gsfc_KoopaTroopaBeach2 - 3 *
Gwii_DKSummit - Gwii_KoopaCape - 1
The two gaps with the asterisk have gaps of 25 rather than 15, but we can just assume they're simply spaced out more as only three possible tracks fit between them anyway. So through this, we can determine quite a bit about upcoming courses coming to Tour, gap by gap:
- Either one of the Wuhu Island courses or Boo Lake (depending on the name they use internally) would fit here.
- Luigi Circuit (already datamined) and two other GBA courses would fit in there. There are a lot of potential options, reflected in the image above.
- Boo Lake (if it is sorted as TeresaLake) or Yoshi Desert go perfectly here. There's the potential for certain DS tracks to fit in too but those appear unlikely.
- Two perfect spaces for Shroom Ridge and Peach Gardens.
- Three spaces that perfectly fit the three datamined GCN courses; Waluigi Stadium, DK Mountain and Mushroom Bridge / City.
- The only courses that can fit in here are Luigi Raceway (already datamined), Mario Raceway and Moo Moo Farm.
- Donut Plains 3 is the only option.
- Ghost Valley 2, Ghost Valley 3 and Koopa Beach 1 are the only options (and the former two have leaked previously).
- Could either be Dry Dry Ruins or Grumble Volcano based on the existing datamined options.
Keep in mind that a lack of gaps does not mean a course will not be added to the game, as the list has been updated regularly between Tours and new gaps are added easily; if anything it just means missing courses won't be showing up in the immediate future. This is also why it is impossible to entirely rule out Broken Pier even if Boo Lake appears to be more likely now; there are other options that fit into the available gaps and another could be added between Bowser Castle 3 and Cheep Cheep Island anytime.