I'm not sure if this is the result of a broken setup on my end but I was unable to compile "cpp3ds-template-emu" until I added "Qt5::Core Qt5::Gui Qt5::Widgets" after "cpp3ds-emu" in CMakeLists.txt at line 44.
So that line now reads:
set(CPP3DS_EMU_LIBS cpp3ds-emu Qt5::Core Qt5::Gui Qt5::Widgets sfml-graphics sfml-window sfml-system sfml-audio openal GLEW GL jpeg freetype vorbisenc vorbisfile vorbis ogg ssl crypto pthread)
Works fine now. Brilliant work thus far, btw!