Ginger is a good choice. I used to wonder about why some of this stuff is so expensive. Well, a contributor here (can't remember their name) clued me in with her experience that the cheaper stuff rusts.

Anyway, I'm not a tile guy but if no one else responds, I'm fairly sure that the baskets can go in afterwards.

HOWEVER, good idea to know where the baskets will be installed when they DO arrive and make sure there is "blocking", i.e. wood for the installer of the basket to drill into. Of course, you can always use anchor screws (wingits, etc) but if your wall is open now, "blocking" is best since it covers all bases.

Also, once you have the blocking (or even if you decide not to block), take a picture of your exposed walls (especially shower) before tiling. Good idea to know for future installations. (Block if you only "think" something will go there if you have a chance i.e. for grab bars when you get older?.)

I haven't even got to the point where niches will be an option and I'm going with Ginger baskets - easier to keep clean, IMO.

That's the problem why I can't have the niche. the drywaller got there and had the Duroc up before I got home to remind him there was a box for the niche. One of the kids let him in when I wasn't expecting him.
He did reinforce for the grab bars but didn't block out for anything else.
Hopefully the basket will be ok. They are old enough to not swing on things anymore!
Thanks for the input.

We just remodeled 2 bathrooms and put Ginger shower baskets in each. DH doesn't like niches and we were going for a hotel style look. The baskets were installed after the tile work was totally done - actually several days after cement board, tiling and grout was completed. The baskets look great.

As elphaba mentioned, blocking is a good idea....my tile sales guy said to silicone the screw holes too My GC put blocking up, but told me that it didn't matter because the screws didn't reach the plywood block. I think the screws Ginger provided weren't long enough because there was this decorative piece that is used so the baskets aren't flush against the tile. I am a bit worried about that since I don't want the baskets to loosen over time. We are being careful about not putting more than 1 shampoo bottle and 1 conditioner bottle in each. My GC installed Ginger baskets in my friend's shower the same way 3 years ago and she hasn't had any problems. Good luck!

If you wanted to know about Wingits (which I have only heard GREAT things about but haven't used them myself), the website is at:
www.wingits.com
If you are obsessive, like some of us here are, you could buy larger screws for the Ginger baskets (or have your handyman buy larger screws - stainless preferred) and probably could use the wingits with those but since I'm not a handyman either , I think I should stop here before I get into too much trouble. (LOL)
You could also probably add the Wingits later if a problem developed or baskets seemed a little wobbly/shaky. Another good reason to use baskets, lots of things can be done later rather than earlier, I think.

I'm taking a deep breath, pouring wine and letting it go. Obsessive is a too nice a word, crazed over this remodel is more like it.
I love the ginger hotelier line. It will be beautiful. I want the long rectangular one and will mount it on the long wall over the grab bar.
My niece is helping me figure out how to post a photo for the after shot.
Glad everyone likes the baskets.