Most Sanitisers/dehydrators contain acetone so there is no need to use both products.
Just take a little more time to 'scrub' each nail with the dehydrator and a lint free pad (not just wipe over) and make sure you make the extra effort to go right around the sidewalls and eponychium to remove all traces of oil that have gathered there in the grooves. This is all you will ever need to do. Takes about a minute if you spend 5 seconds per nail scrubbing.
Using soaps and water is something I do not do before polishing. I do not like to wet the nails any more than I need to before polishing. Using a nail sanitizer/dehydrator is quicker and easier and you don't have to break off while the client goes to wash. I also think the polish lasts longer when you avoid water.