> - Find and replace a variable > - Finding all references
I think the basic search tools are pretty good. I can't say I expect find and replace to be super common. I would prefer to do such things one at a time.
> - Change a variables type
I would say you really shouldn't be doing this too often. It's compiling to statically typed code under the hood so this will frequently cause a lot of breaks. You can do it, and it will highlight all the areas where this breaks things (maybe more easily than c++ might tbh). And if the types are compatible, that might mean you have to do the annoying step of redrawing lines to the same var with a new "node" representing the proper type.
> - Merging changes from multiple commits
This is hard and not good. The most difficult part about blueprints.
> - Refactoring
I tend to think this is pretty easy. Maybe easier than in code. I'm a big fan of collapsing all nodes into subnodes. So every individual step becomes one high level node. You can also "collapse nodes" into a function itself. You want to minimize the number of nodes you're looking at any given time so it kind of encourages good practices on itself if you're competent.