Unless I can step through original source code in debugger, watch variables etc. etc. I could not accept any source to source translator in my practice.
Cppfront generates #line pragmas which tell the generated .cpp file which source lines to "blame" for each piece of generated code. This isn't something new and fancy for cppfront, it's a bog-standard pragma that your debugger already understands. So it will work the exact same as your current debugging workflow even if you mix cpp and cpp2 source files.