Consider something like this: https://www.amazon.com/simplehuman-Triple-Shampoo-Dispensers-Stainless/dp/B002YNQX16/
Then you can pick any products you want to put in it... and it won't clutter the floor or shelves in the shower/bath.
As for the specific products, that's soooo personal preference. Try going to Target or Walmart and just smelling them all. But try to find something you can get in bulk too (check the warehouse stores for what they stock).
This is my exact struggle. I would love it if I could find a toiletry showroom so I could sniff sniff sniff. I think there are probably some in LA. But ... LA.
I did order a sampler pack from one vendor that I found who offers it that I can try. But in the end I may just have to chunk a rock and order something, relying on prior reviews.
They have eco-friendly packaging, and you can have your own custom logo, etc. They are also going to be in compliance with the California eco-legislation banning hotels from having small shampoo bottles, and will provide larger bottles (which is what Marriott is doing in 2020, but they will have large bottles set out to create a more luxury presentation vs. the tacky cruise ship type of mounted wall dispensers.)
My properties are in Calif. For marketing, as an extra bonus for your guests, you can promote that they are made locally in California. Noble Laboratories, Inc. dba Fullers' Soaps
For towels and sheets, go all white. A truly professional service won't mix up your linens (I use one and they bag and tag them, and as an extra measure, the footer of the bed sheet (part that is tucked under the mattress) has my code on it.) Guests don't want bed linens that hide stains. After all, how would you know for sure that the sheets were clean if stains could be easily camouflaged? White sheets are one effective way for hotels to prove their standards of cleanliness. If you doubt, here's an article why every hotel (including luxury) has only white linens and towels: The Real Reason Why Hotels Use White Bedsheets | Travel + Leisure
I haven't been on a cruise since 1989! So I'm not sure what kind of dispensers you mean but I totally agree that I don't want anything commercial-looking. I'm doing a personally branded version of this one I found on Etsy. I think I've figured out how to do it much more affordably than you can find them on etsy. (huge sigh of relief because I'll need probably 20 per property and that adds up).
I'll check the fuller site more carefully. I only saw tiny toiletries at first glance. I would love to source as locally possible... For sure I need something that is cruelty-free and vegan.
Do you source your towels from the commercial/hospitality Costco? I actually use those in my camper and they are quite nice, IMO. Do you have any issues with the CA hard water causing greying of your towels? Not sure where you are, but I'm in Mammoth and its a small town, though popular with visitors. Our cleaners/laundry do their best, but everything is a struggle when there's 20 feet of snow on the ground and the town is busting at the seams with visitors . . .
As for bottles choose clear and not colored ones unless they are light blue or some "in" cosmetic color.
For the logo on the bottles and the labels be sure to use water proof ink or labels.
I always choose colors which complement the bathroom colors where the towels and soaps and toiletries are kept, including the spa robes and slippers.
So in my case they are a soft beige and white, the linens are colors to complement the bedspreads and draperies and the accent pillows carry the stronger colors.
Keep in mind that with larger bottles there will be more waste - the human nature.
As for shampoos and conditioners it is almost impossible to keep the right ones on hand, since everyone seems to have processed hair in one way or another and each requires a different composition of chemicals to keep it in shape.
Shower caps may seem old fashioned but are welcome with my guests.
Plush bah mats and towel warmers make up for a cold day on the slope and sink the guest into the luxury of warmth and comfort.
I would study the clientele for this new property carefully - age, income bracket and length of average stay and then tailor the supplies accordingly.
Most people will prefer to use their own toiletries - the exception to the rule are the ones who like to use everybody else's stuff.
If this property is really upscale then check into monograms - they are not that expensive if done in bulk and the laundry service will not mix them up easily.
Also pay for higher grade detergent and softener with a very faint scent.
It all in the senses.
Edit: forget the labels you said that already.