Thank-you. The company sent me the wrong item, I asked for the Laticrete Latasil Silicone Caulk Sealant, but they just sent regular Laticrete, which is OK since it will also get used. The shower is waterproofed to our city code standards, but various contractors waterproof showers "properly" in other methods. So far no water seems to get in behind the wall, it's very dry back in there and we don't use the shower at all when cracks appear - not until it is repaired. A tile contractor (the only one I can find who's website says they do "tile repair" and that comes recommended) said he actually won't come and make these kinds of repairs, he will repair his own work but that of others he removes and re-does it all, because he wants to be able to guarantee the work. I have not found anyone else willing to do the repair. So it's up to me, and I just want to make sure I have what it takes before tackling it! Thank-you for your advice about the caulk.

Thank you! That's exactly the kind of expert advice I needed. The front face of the tub deck is also tile. My instincts were to grout, but I didn't want to make a mistake and be sorry later.

Yep on everyone's advice re- the caulking. As for sanded versus unsanded grouts, there is only one factor that determines which is to be used, and there are no exceptions, regardless of what you hear about high gloss or polish, or soft glaze, etc.. The ONLY thing that determines whisch you should use is the joint size. Less than 1/8" you should use unsanded grout. 1/8" and over, use sanded grout.

Caulk goes anywhere there's a change in plane. Which covers pretty much everything you've listed above. And it should not be installed over grout; rather, the grout should be removed if they put it there, and caulk placed in the clean area.