1. Copy the .nds rom to your card.2. Place a .txt file in the /Book/ directory3. run conv.cmd4. your book should convert into .dr files in the /DRBook/ directory5. Enjoy your books with sideways reading action!
I don't have a wii u anymore to test it myself, but if homebrews are not visible on the wii u menu I think you can press L + R + minus to open the plugin menu, there should be an option called "homebrews on wii u menu" or something similar
Or when your player dies, you can say in code, if enemy exists, do nothing, but if enemy does not exist, then create enemy at certain spot. (This would be a pain tho for lots of emeies)