The Lancet article proves that when someone consumes olive oil and lemon juice, the result of digestion causes the production of potassium carboxylates. The physicochemical properties of such "soapstones" fit the observed physicochemical properties of the green blobs. Therefore by a process of logic, green blobs are soapstones.
Therefore by Occam's razor, different colours of blobs are likely to still be soapstones (since I imagine it is bile pigments that colour the soapstones).
Occam's razor - a very good principle to remember. Deductive and inductive reasoning and dialectic method - also very useful.