I've found a lot of places claiming that he produced these translations, but no one seems to know where they were published(or whether they still exist at all in any format, for that matter).
2 Answers
As far as I know, he only translated Guinevere, Godiva, and Œnone. They were published in one volume by Pietro Gibelli of Bordighera in 1906.
I have a digital copy (images only) and I may find time to OCR it.
https://www.dropbox.com/s/bvnfj4qxq401lkf/Gvinevero.zip?dl=0
Mi lastatempe informiĝis, ke la tradukoj troviĝis en arkivoj de Biblioteko Hector Hodler.