Here is a video proposal :
Tell me what you think
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Partial solution (adding reroutes to all unused inputs and replacing them) :
If you prefer to read or didn't understand this rushed video :
So you have a bunch of nodes and you want to add reroutes to their inputs
Voilà. Now you can replace those reroutes by any node with Shift+S. And if you need them to have specific parameters, don't forget Right-click > "copy to selected" to apply your changes from the active node to all the selected ones.