I frankly don't know how Alchemist handles things, but I can answer your question a bit, if you manually modify the Crates.igz file for the level of choice, using a Hex Editor to open the file.
Now to answer your question proper, as long as you change the string code of the igz file with one that contains the same total number of letters, you are able to change certain crate types to your heart's content.
A few examples include:
Bounce to AkuAku or Random
Basic to Nitro or Arrow
The game is able to recognise some of these combinations since you don't change the code too much, but one particular part called Crate_"Insert crate name here"_Spawned_gen.
For example) As demonstrated, you can change any of the above strings in the code and the game won't crash at all (from the crate modifications at least).
Crate_Arrow_Spawned_gen. or Crate_Nitro_Spawned_gen. or Crate_Basic_Spawned_gen.
Crate_Bounce_Spawned_gen. or Crate_AkuAku_Spawned_gen. or Crate_Random_Spawned_gen.
I'll test for more possibilities going forward but for now, I hope this clears things up a bit.
Now to answer your question proper, as long as you change the string code of the igz file with one that contains the same total number of letters, you are able to change certain crate types to your heart's content.
A few examples include:
Bounce to AkuAku or Random
Basic to Nitro or Arrow
The game is able to recognise some of these combinations since you don't change the code too much, but one particular part called Crate_"Insert crate name here"_Spawned_gen.
For example) As demonstrated, you can change any of the above strings in the code and the game won't crash at all (from the crate modifications at least).
Crate_Arrow_Spawned_gen. or Crate_Nitro_Spawned_gen. or Crate_Basic_Spawned_gen.
Crate_Bounce_Spawned_gen. or Crate_AkuAku_Spawned_gen. or Crate_Random_Spawned_gen.
I'll test for more possibilities going forward but for now, I hope this clears things up a bit.