Very good theory i'm of the same mind, many evidences show that Sanji's power is channeled from his emotions, especially Hells Memories.
Also
@Soleus the Sora explanation, Sora's ideal vs Judge's ideal through the comic book and the connection to Vegapunk with his failed experiment which Momo ate. All the pieces are coming together and it comes back full circle, it would be a narrative worthy of Oda's work.
Just one thing about the invisibility, Niji has shown to be able to activate this ability without his raid suit on while his powers are electricity related. So if Sanji awaken his modified genes in a permanent manner or strictly for the duration of his emotional state, in theory he should be capable of attaining invisibility without the raid suit and to manifest his own exoskeleton as well. Then of course all of these abilities would be superior to his brothers, thanks to his emotions.