it's a shame that they're not as accepting as we'd like for CDLC, shouldn't it be treated as a mod for a pc game that extends its' lifetime? like half life when the very first iteration of counter strike got released.
the songs you mentioned are played on a 5 string bass. CDLC authors usually treat the red string ingame as the low B, and the yellow string as a normal E and so on.
i was thinking something like a "checklist" for each song to see if you have every drum needed to play it. for instance, "you need 3 toms/2 crashes/2 rides to play this song". sorta like needing a capo to play some arrangements on rocksmith.
i can maybe understand not doing keyboard/violin/etc charts, but this game would be absolutely perfect if there was a drums addition that had the same amount of focus as the guitar.
vocal charts are cool, i have a ton of dlc i've made for myself that have the vocals chart as a bonus arrangement, it's always fun to play along to it. it also tells me the range of notes i can improvise over and still keep in tune with the melody of the vocals