I love your solution @chris_homburger , since often you just need to think from another angle to get it working 
There is a nasty way to work with lists/table lookups out of a cell.
In LIP2, I needed something similiar to calculate, if you have the right items in your inventory to interact with an object or not. The only way I could find was to flatten these “formatted lists” using “totext()” in a formula map – just to split it up again to a real and clean list.
For your example instead of:
=[Fruit salads].Fruits.ListCombine().Unique()
you could make
=[Fruit salads].Fruits.ListCombine().FormulaMap(ToText(CurrentValue)).split(", ").Unique()
to get the results.
Note that in the split formula you have to use ", " instead of “,” (so with a space), to get it right.
To get the leftovers, you can filter the fruits down (I named the first formula “inUse”, so it represents our in use list)
=Fruits.filter(in(fruit,inUse)=false).fruit
Maybe this flatteing could also be a workaround for your importing case @Philipp_Alexander_Asbrand-Eickhoff?