The Warp Room

I've been messing with the Alchemist tool to mod the game for a while and I have few questions regarding what, if possible, you can do with it.

1. Can you add stuff from other levels by using it and making it into a proper .alcmod? (even if it breaks the game)

2. Would it be possible to add the controllable camera, as shown in this video, using this tool?
https://youtu.be/FAJJLFq7vpU?t=1140

3. Not really a question, but I don't seem to be able to open the "L121_SlipperyClimb_Bonus_Brio.igz" file, neither on my PC nor Laptop and unsure if it's the issue on both my ends or in general. 

Thank you in advance!

I believe I can help with your second question.
I first learned this from BetaM and I've managed to recreate it with alchemist, I do however suck at explaining things so I made this screen recording of me doing it

https://youtu.be/lU-VUetvwMo

Not all levels have the LegacyCamera.igz but some ones ive checked which do are turtle woods and toad village

As for your other questions, I haven't figured out any ways to ADD stuff to levels using alchemist as you cannot import things into the igz files only the pak/alcmod file you are working on. Replacing and changing are the only methods of modding anything using alchemist to my knowledge, using a hex editor such as hxd may allow you to add things if you know what you are doing but I would have no idea how to do that.

For your third question I also am unable to open the extracted file if I use alchemist but using nst pak explorer to extract it then opening it in alchemist did seem to work so I linked that under this.
https://thewarproom.com/showthread.php?tid=63