I’m not sure if it helps, but perhaps my recent observations may increase your insight as to how blocks are turned into lists and vice versa, and associated quirks.
I’ll have a look at your INTO DEFINITIONS block one of these days, that may help me understand as well 
Other than that, all I can say is: metaprogramming Snap! is mostly a matter of trial and error learning by doing.
Btw where can I find a working version of INTO DEFINITIONS ?