For non-jazz style, and with a grand, you might have to get in closer, near the hammers for the definition and strike tone. Often an upright (of quality) records better for 'pop' sounds than a grand, as the low end will need to be carved away, especially with an acoustic bass playing the bottom register...
I'd try the KM184's in XY or spaced pr
first, with a possibility of using the U87 as a solid 'centre' mic for meat on the piano: you might be able to get away with less bleed using these cardioid mics, and yes - try the 105 as the vocal - I think it'd be better starting this way, and using the U87 if the 105 isn't cutting it. Bass often records well with omni's, and I think the TC30k would be good, moreso on the bass because you can get in really close with no penalty for proximity. Also, they (TC30k's) are a bit noisy for my liking, and tho I've used them on piano before, I don't like their inherent self-noise, esp. on quiet piano passages, but - you did say it was more a 'pop' vein so, this might be the right thing for the recording too...
IME, TC30k's work best for pop piano in close to the hammers, and check phase if you're doing anything adventurous - getting the piano 'distinct' sounding will be the challenge, and the more mics you bring in will more than likely add more ambience, and less clarity. A solid 'centre' - either with the U87, or the Neumann KM184's would be my objective in this situation. Omni's on piano will often tend to smear the clarity, esp. when in spaced stereo.
There is no right and wrong, just what works. I hope you have good monitoring for playback, because that is almost always the toughest thing in piano remotes. Make sure you have enough time to go through a couple of possibilities, and if you can accurately monitor the recording, base your decisions on that. There is nothing worse than rushing through a remote, and finding out that the piano is recorded poorly (this is from my own personal hellish experiences...)
All the best, and let us know how it turns out!