Lately I’m making extensive use of Roam Research’s Cycle version functionality. Basically it allows every node to have multiple versions:
There are many use cases for this; personally I use this to rapid-fire brainstorm different versions of a point in the outline (branching). There’s something liberating about hitting the equivalent of cmd+N and have a completely blank slate inside an existing document to work with, with history preserved. Also great for revision.
There are probably a gazillion workarounds to achieve something like this in current version of Bike (though not as neat), rely on macOS version control; or just have versions stacked on top of each other.
What’s neat about RR’s versioning is that once you select it, there’s only one ‘canon’ version. Other versions do not interact with the outline or graph, but they’re still there if you need them.
So…I wonder if Bike’s extensions could allow for something similar? 
Maybe dump different versions of a row+descendants into an invisible part of the outline, and let them be recalled in some form?