This is a late reply, but I wanted to make sure you got a complete response.
The features you desire are not supported on Sankey diagrams.
Sankey uses the natural sort for the event. Explorer does not have custom sorting, I think that is only for reports in Designer. At VA 8.2 and higher on Viya, all these features have been merged so it would be possible.
The time variable is not shown because it is only used to determine the sequence of each transaction. Two different transactions with the same sequence but differing times will be merged into the same path. Therefore, the time is not necessarily unique for any particular event shown at a stage in the Sankey diagram.
You could try the vertical layout option; that would put 'Bottom 99%' on the left side of the graph and 'Top 1%' on the right side, so left-to-right you have an increasing order.
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