Also, the cost of the quartz is dramatically less if I go with seams (of course) and we are really trying to contain costs on this project. I used a whole slab for our other drop-in tub which we did in granite, but wondering if I can get away with it for this project. Is a quartz deck going to look horrible with a seam - I'm guess they'll recommend a diagonal seam in the corners. Thoughts?

The style of the hexagon mosaics does not mix well with the pebbles. Use the hexagon for the shower floor as well. Or, if you love the pebbles nix the hexagons in favor of a larger floor tile in a coordinating color to the pebbles (not a marble look). If you are using the subway tiles, you should carry them around the tub apron; it's not busy. What would you consider to be less busy?

Skippack - good suggestion. The hex tiles are more important (daughter's must have) than the pebbles so they'll have to go. Maybe I can use them in the shower niche for some kind of accent? I have put pebbles in two other showers and they really provide good grip and feel for the feet, but we have larger format tiles in both of those rooms so I have to agree it might be too much. Not sure what i thought would be less busy on the apron, other than larger format tiles or sheets of quartz maybe? Subway would be less expensive and simpler though.

Install your accent tile in a vertical stripe, floor to "top of tile" instead of the old school horizontal band.

So, if she loves the hex, just use them in the niche as well as the flooring throughout. Agree with Sativa on the quartz fabrication, 4 pieces are fine for the surround.

hex on shower floor and in niche.

Just make sure you get the proper bullnose for around the niche, as shown here.

Slab stone on tub deck and apron. As well as niche bottom and sides. No more than 2 choices for any tile.