Hi Gary,
At dinner I've used hummus in pasta with rehydrated grilled veggies (merely add a touch more olive oil and a little extra water to reduce the thickness when using it for pasta). At lunch it goes in wraps with chicken as a sort-of chicken salad – also with veggies as a dip (sometimes I'll sneak a cucumber and some carrots into my husband Bryan's pack for this) and merely on it's own with pita. I like it just with lavash or a sturdy cracker too.
I have several hummus recipes in my repetoire and try to stay away from the pre-dried mixes so that I can really make the flavors the way I like. It isn't unusual for us to have 3 differently flavored hummus like dips on a trip.
Dehydrated sour cream only works as a minor ingredient when you are drying an entire dish. Choose a low-fat or fat free variety and that will help with the shelf life. I figure if I am running the dehydrator anyway there is no need to spend the money on powdered.
Yes you can dehydrate olives and saurkraut and pickles… but be forewarned… it's a smelly process. I dry olives all the time for our trail pizzas and to add to wraps as they are my husband's favorite. I also make a mean olive tapenade that is very light when dried. It's terrific on crackers. Puttanesca sauce, which has olives in it, also dries beautifully. If you dry these types of things then do so in the warmer weather so you can have a window open and a fan blowing the air to the outside – this will reduce the smell substantially.
PS I know you aren't trying to be facetious. Keep in mind that I was once like that… full of questions. Also don't be afraid to experiment as you never know what you'll come up with.