that's really nice work you did there! I'm very impressed from the Name Selection Screen - that must have been horrible to modify!
If you ever want to continue that translation perhaps these infos help a little:
The stages 11-13 are included in the normal Super Bomberman 5. To unlock them use a Hudson Super Joy Card controller. Have the X switch on the controller set to the middle and on the title screen hold X for about 6 seconds. A sound will confirm on success.
If you play with an emulator you can use a hexeditor and change byte $01EA in the SRAM from $00 to $FF.
Some time ago I hacked around in that ROM too. I took some notes about the Stage Selection Sprites. You can find them here.
Feel free to use this if it helps.
The space for the sprite-data was very limited and I solved this problem by moving the memory area from $03DC4A-$03FFFF to $0CDC4A-$0CFFFF. Therefor the pointer at $0016DE was changed to point at $8CDC4A.