I've been holding off on testing your other IPS files since I know your head is in the right place with this project. Now that you have something fully finished, I can offer some feedback and thoughts.
As you know, I loved the multiple paths concept. It really felt like I was playing Palace Acropolis all over again, but in a different setting with different obstacles. Most of what I have to point out are inquiries rather than bugs, so that's a plus. I've also played this level four times now to ensure I didn't miss anything major (though knowing my luck, I probably did).
This could potentially be the first level the player encounters the Frostee in, so it might be worth noting that you can't actually jump on them normally (I think you still have a message box free, don't you? I only noticed the second one used at the end of the level).
Do you have a specific tilemap you want me to set these to, or are there just no graphics ready for it yet?
This is actually a problem with the sprite itself, but it can't damage you while you're on Yoshi.
Very minor nitpick, but the firebar goes behind the ice pillar here.
You wouldn't be able to raise this ceiling up a tile, would you?
I think I get what you're trying to do here with blocking off the SMWC coin (that is, if you've pressed the yellow switch, you'll need to run back, get the shell, bring it here, and kick it at the blocks to pass them while they're coins). I guess it just seems a little odd since you could potentially have a bunch of mushrooms popping up (and if you hit the top one, it'll get stuck). Did I miss another solution, or is this it?
Looks like I still need to remap these too (noticed it in my level as well).
No screenshot for this one, but I do have a question: other than getting all of the SMWC coins, is there any reason the player WOULDN'T want to enter the pipe right at the start? It takes you 75% of the way through the level, and it's just a matter of running right to the end. I guess if you're a non-completionist then you could just skip it all, but something about that seems a bit iffy to me.
(quick note: keep in mind that I actually haven't read others' reviews in this thread at all since I wanted the level to be completely fresh for me when I played it. If I missed anything, or something has been addressed already, do not hesitate to let me know.)
Aside from what I've mentioned, this is a fun and complex level. It's also the perfect difficulty and length for world 7, though I expected as much. Nice work overall.