Sorry, but I didn't get round to reply until now. Anyway, in the next days (including this one) I should have time, since I have vacations, so I'm sure that I'll be able to watch the stream live, looking already forward to it.

I also still don't have a twitch account, so in case I'll have any comments, ideas or whatever, then I'll have to post it here.
Great videos by the way! The one with the mushroom looks pretty hard.
The matuvu combo with the green gem in part 3 is actually possible, only the powerup might cause trouble. I still prefer your version, since it's definitely easier, while there's no big difference in points.
I didn't make an overview as I wanted it to be, but here's a list of the remaining ideas / potential improvements (Yet I didn't take the new videos from Cut into account, so it's already outdated

, I'll edit this post soon then).
Part 1: 14550 - 14550 (outdated)
1.) Take the six gems near the red can, roll of the ledge, kill the hoodblaster near the wooden door, then continue with the piggybanks and the other hoodblaster on the bridge. (Cut already managed to do the beginning)
2.) … after breaking two piggybanks out of the three and collecting its gems, jump on the right ledge of the bridge (use the third piggybank to keep the combo alive), kill the hoodblaster and quickly jump on the platform with the three yellow gems and get them, then break the piggybank above and take the gems. (I'll test this soon)
3.) Some other minor stuff in the big area with the green liquid. (I'll test this soon too)
Part 2: 16140 - 30690 (outdated)
1.) Somehow try to include the first matuvu in any combo.
2.) Some other minor stuff. (I'll test this soon too)
Part 3: 11570 - 42260 (outdated)
1.) Pass all three gems quite at the beginning and include them in the vine combo.
2.) Somehow include all gems on the vine in the green gem matuvu combo.
3.) Get the green gem for 6000 combo points by using a rolling SJ.
4.) In the last cage combo make somehow more gems spawn, in the optimal case 2x12.
Part 4: 22400 - 64660 (outdated)
Part 5: 3000 - 67660 (outdated)
Part 6: 3730 - 71390 (outdated)
Part 7: 39770 - 111160 (outdated)
1.) After taking the first green gem, convert at least one of the two remaining lums. (going by a few tests it should be impossible)
Edit: I just read your post, Maz. Nice findings, they're definitely helpful!

I actually found a spot where you can perform a kickflip shortly after the lone red gem. This allows you to combine this gem with the next hoodlock, leading to a improved green gem combo. With your finding we can already play following combo: Hoodlock, five yellow gems, kickflip, red gem, kickflip, hoodlock, etc.. If we find a way to perform another kickflip in the cavern at a spot between the first hoodlock of the combo and the yellow gems before, then we could possibly make the combo extremely long, so it's definitely worth to take a look at it.
Edit 2: 270 points improvement!

I found a way to get the gems in the room with the first knaaren with a powerup and afterwards reach the next area. You can see it in this video:
https://www.youtube.com/watch?v=N8sdBP5qZTY
I added some comments to the video to make it clearer.