A marble tile with large tiles is a bathroom of depth as far as I am concerned. Sure you can put down non-skid mats but you have to have them cover every square inch your feet may land or you will skid. I am currently renting a place with 12' square marble tiles and I actively wonder whether this will be the shower that kills me - seriously. Not to mention that there are no grab bars in the shower which also has the 12" polished marble. I honestly don't think honed marble would be less slippery but you should verify what the COF - friction level is and make sure it meets safety standards. I am having marble mosaic floors put in the bathroom - shower and floor and the grout means they are grippy. Modern grout doesn't have the same issues as older grout does especially if one uses grout in a sot gray color which is more forgiving than white. Also, periodically one can just have a professional come in and clean the marble and grout. My building does this with common area floors and they look like new after 25 years.

I generally like a contrast, and I like shiny splashes that light reflects off of, but if using marble, I'd probably stay with the honed for the splash too. The polished will get splattered -- maybe not a lot, but I wouldn't want to see those dull spot against the polished. On the honed, I doubt anything would be enough to bother me, and if it was, I know I could buff it out.

Matte, Suede is not different to look after than polished. If it was Caesarstone matte, yes you may find it a little more unfriendly Suggest you read this https://stonebenchtopcleaner.com.au/sds/Quartz_Care&Maintanence_Essentials_(2018web)DSA_Rev4.pdf

Honing, leathering or polishing is best done at the quarry with the machinery to handle large slabs of stone. Some large fabricators have equipment to alter slabs at their workshops, before they are cut or installed, but it isn't happening in your home with quartzite slabs that have been cut and installed. If someone says they can ... make sure to have a written contract and check that they have insurance by calling their insurance provider! Buyer beware.