Names are hard. Scuba Steve will find your files with the same base name and allow you to cycle through them.
There are two commands: 'scuba-steve:toggle', scuba-steve:start-dive'. Dive will refresh the path cache, and toggle will cycle through similar files (foo.hpp, foo.cpp, etc).
Activate the package with scuba-steve:start-dive. This will build the path cache for cycling between files. scuba-steve:toggle will switch between the files once the path cache is generated.
'atom-workspace:not([mini])': 'alt-o': 'scuba-steve:toggle'
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.