I cannot find where any of your links say that there was a believe in a literal change, i.e. a change to observable properties.
You won't be satisfied unless the actual word 'literal' appears? It appears in the first paragraph of the Stercoranism link, and again in the second paragraph.
"the 9th century Carolingian theologian Paschasius Radbertus... wrote an influential tract around 832 upholding the literal interpretation of Christ in the Eucharist". He supported the literal change, but said that the holy bits dissolved before becoming poo.