Something like this likely.
CustomCommandParameters="/c ren “%convertedfile%” %convertedfilename%-1.%convertedext% & “C:\Program Files\MCEBuddy2x\ffmpeg\ffmpeg.exe” -i “%workingpath%%convertedfilename%-1.%convertedext% -map 0:v -c:v copy -map 0:1 -map 0:2 -map 0:3 -af dynaudnorm=f=150 -c:a:1 copy -c:a:2 copy “%workingpath%%convertedfilename%-2.%convertedext%” & del “%workingpath%%convertedfilename%-1.%convertedext%” & “C:\Program Files\MCEBuddy2x\ffmpeg\ffmpeg.exe” -i “%workingpath%%convertedfilename%-2.%convertedext%” -map 0:v -c:v copy -map 0:1 -map 0:2 -map 0:3 -af loudnorm=I=-16:LRA=11:TP=-1.5 -c:a:1 copy -c:a:2 copy “%convertedfile%” & del “%workingpath%%convertedfilename%-2.%convertedext%””