Hello caseyprep82. Yes, you can prep ingredients for okroshka in advance, but you need to follow a few specific guidelines so they do not lose flavor or become soggy.
Here is how you should handle it:
1. Chop your cucumbers, radishes, meats, and boiled potatoes, but store them in separate airtight containers in the refrigerator.
2. Do not salt the vegetables ahead of time, because salt will draw out the moisture and make them soggy.
3. Keep your fresh herbs unchopped until the day you serve, or chop them and store them with a dry paper towel to absorb extra condensation.
If you keep everything separated and dry, it will turn out fine and save you plenty of time during the week.