This isn't about grout...before you grout have you put poly on the walls behind the cement board and do you have the correct slopes on your liner as I don't see any topical waterproofing in your shower. I also worry about the screws on the top of the curb as they will penetrate the liner wrapping over the curb.

Thank you for the concern Jeff :)

As far as I know everything was done to code, proper sloping and liner installed, etc. Screws were a special kind, and curb that will be used is all one piece as well for added protection. Everything had to pass inspections as we went but I will ask GC again tomorrow ... he is used to my questions ;)

If anyone has thoughts on grout I'd still love to hear

OK double check, your niche definitely needs waterproofing IMO. Sorry to change the subject on you a bit, but any picture of a shower posted on here gets picked over by the shower police so if it wasn't me it would have been someone else. By the way I like your tile as I did a 2" white hex on my floor, I don't know what color of grout was used, it was TEC and I just asked for light gray.

"As far as I know everything was done to code, proper sloping and liner installed"

Code does not mean it is correct. I agree with Jeff. Trust but verify and the visible clues tell me and I am not a tile pro that this is not done correctly.

Thank you millwork for your concern as well. I actually watched the liner go in over a sloped base and the liner passed the leak test. I also watched the dark gray concrete like stuff go on afterward that they "sloped everything with. Additionally, GC told to make the tile no larger than 3" tile for proper slope reasons as well. The white you see around the drain is the stuff the tile guy added with metal lath 2 days prior to tile install...leveling the main floor while ensuring slope in shower as well. These pics are incomplete as they were taken "during" install.

I will definitely ask about the niche this AM, but I have been completely satisfied with how thorough their work has been thus far throughout my house as well as what he did at my brothers' homes....but I'd rather ask to make sure, so thank you.

Does anyone have any opinion about the two grouts colors? Maybe I will repost?

I used several different colors of grout in my bathroom remodel because I had several different colors of tile which were used and I wanted the grout to blend into the tiles rather than be a design element.

We understand your looking for a grout color recommendations. Comments above are concerned for your $$$. There should never be fasteners in the curb as shown for a liner installed base. Also a pre slope under the liner is required and often skipped. Here is a detail to help you and your builder understand.

https://www.google.com/search?q=tcna+shower+curb+detail&tbm=isch&tbo=u&source=univ&sa=X&ved=2ahUKEwi6ldq74JffAhUPHDQIHdaKCQ8QsAR6BAgFEAE&biw=1301&bih=590&dpr=1.05#imgrc=bSbtMcJjsGbzEM:

This type of wall construction is fine, if old school, with a poly vapor barrier behind it, but I don't see how the niche is possible to install and still keep a vapor barrier in tact. Of course this is speculation and the OP needs to get the real information from the GC.

I'm glad a topical membrane went over the niche. I hope all other wall corners, seams and screw heads were done too. It would have been better to put the Laticrete (either Hydroban or Hydrobarrier) on the whole shower and certainly the curb needs to be waterproofed now that the liner is presumably punctured by all those screws. You don't have much tile in the shower and you should consider getting the setter to pull that up and scrape off the thinset and cover the whole shower and curb as was done in the shower I showed above, it will take half a day. Also the finished top of your curb should be a single piece of material, not tiles with grout joints, to further minimise water penetration. Sorry this has gotten away from grout.

For some reason several notifications popped up today that I never knew were on this thread or a couple others.

I thought it may be helpful to some who may read through this (and reassuring to those who were concerned) to see in first two photos the watertight way the shower was structured,

then in last two photos are the colors of grout/what I ended up doing (per my original purpose of posting this question on Houzz) :

^^^This red/pink stuff is the waterproof material that was put all over the shower/in niche/etc before the tile went on.

And as I had mentioned in prior comments, a large curb was always the plan as you will see in this almost-finished photo :)

*Note: The unfinished window is a reflection and not actually in the shower

Finally, for those who looked at this thread in search for answers to their own questions about grout colors, I went with Tec Dove Gray Sanded Powergrout on the floor and niche (wherever the hex was), and Tec Silverado Unsanded regular grout on the walls with Powerboost added (to make the unhanded grout a form of Powergrout) on the walls...choosing the lighter gray to soften the bright white so that it would work better with the warm white vanity. The Powergrout has posed no issues whatsoever in the last month since the shower has been used. We did seal the floors/walls for additional mold/mildew/stain resistance.

This is a good representation of what the colors of tile and grout look like in reality...the Dove Gray appears a bit softer in person though.