Aww, I’d never tested but I hoped those worked on the BEAM files rather than any kind of source files… 
Ooo really? Any docs on that? (I’m still mentally stuck in the OTP 17 world as that is the last time I delved in to the engine… >.>)
EDIT1:
Hmm, the dialyzer docs says it can work from debug-compiled BEAM bytecode, which the Core Erlang I gave had the debug annotations in it so it would work: dialyzer — OTP 29.0.2 (dialyzer 6.0.1)
Cover seems like it can work fine without the source files but you have to add in the extra decorations yourself (which a language compiling to Core could do itself): cover — OTP 29.0.2 (tools 4.2.1)
And I’m pretty sure the debugger works fine with debug-compiled BEAM bytecode, otherwise various embedded setups would not work? Checking though, and yep, it works fine with debug-compiled BEAM files (in fact it only touches beam files, not source): Debugger — OTP 29.0.2 (debugger 7.0)
So yeah, it should work fine and would open up more abilities and a more simple generator (other than adding cover annotations, does not seem too hard overall). 
EDIT2: Huh, actually it looks like :cover can take an existing non-cover debug-enabled BEAM file and create a new BEAM file with the correct cover annotations, so that is easy too.
