Note you do things like can annotate any graph edge with a weight (or other property) so you can express confidence levels directly. You can then write queries to only retrieve nodes linked by a confidence greater than some value. There are differences in how each database supports edge properties. They can also be proxied by building new nodes to connect other nodes but that get's ugly fast if you need to do any amount of it.
In your case the problem will be building the edges (relationships) in the first place if you don't already have them. Once you have some basic relationships built out both languages will give you capabilities for things like cluster analysis.
