Spaces
Ah right, didn't think about the system trimming spaces.
Out of Range
I have "Variable null (never initialized) on Copy old variable" set to err2 (Pass a zero value).
I loaded a save that has 780 variables and then called the plugin function on variable 790 (intentionally going out of bounds). When I trigger the event that loaded the variable, an error is triggered and I get the error message "Error: WD_OlsSaveLoader: Searching for an old variable out of range." So I don't think the settings currently provide any error handling for this scenario.
Actor error handling also does not seem to handle the scenario either (and switches don't have any error handling).