Why SMB1 is not compitable ? Can't they just put it on the 3DS port *
If either of the two courses use elements that the 3DS version does not support (Example Propeller hat NSMB or the Mega mushroom, slender mario or costumes in SMB)
3DS mario maker does not have AMIIBO SUPPORT, no costumes or Mega mushroom, again i said If the courses are made that contains elements like the propeller hat or costumes that the game DOES NOT SUPPORT. I doubt it would be compatible to download.