Typically you should not change the number of connectors constantly, especially if that same subVI is already used in legacy applications.
If all 1D arrays have equal lenght, make it in to a 2D array and adjust the input accordingly. If the array lengths in a call can be different between inputs during the same call, make it an array where each element is a cluster containing an 1D array.
Alternatively, if there is a small upper limit of the number of input arrays, make a subVI with that number of inputs, then detect inside the subVI which one's are wired (e.g. check for "empty array" or similar).
To add an input to a subVI, create an additional control on its front panel, then show connectors in the icon pane, add a connector, and assign it to the new control.
In the calling VI, the VI is now greyed out because the connector pane no longer matches. right-click on it and do a "relink to subVI" to fix this.