Soul Singer (Bard/Incarnum Prestige Class)

[Grod_The_Giant]

That's not going to change the fact that you are effectively doubling your damage output. And, unfortunately, as long as you reference Inspire Courage (increases damage bonus from Inspire Courage by...), then it will stack with WoC or DFI.

WoC I'm not so worried about, most GMs are smart enough to ban that. But what it can do with DFI is just... scary. Particularly if you have a summoner in the group.

WoC works fine if you apply it before bonuses from feats, items, and the like. Make a note that Songmeld is added after all other modifiers and you should be OK.