WORKS IN TRANSLATION

Again I'd like to bring in a couple of examples from my own field of specialization, and pose this question: is there a generally accepted approach for compiling a critical edition of a work in translation?

for major and universally studied authors, like Dante and Boccaccio, this would seem to be an important matter. Yet, from my own experience, there seems to be a great deal of indefiniteness regarding how to go about this. For example:

Dante's De Vulgari Eloquentia is considered the first Italian work of linguistics, and the first such work ever to be written by a poet. It is an unfinished Latin treatise in defense of the "vulgar" language (which would eventually come to be known as "Italian"), and while it is written in (Dante's medieval) Latin, it is widely regarded (presumably because of its author) as part of the Italian literary canon. The commonly recognized critical edition of this work is the one published in 1968 by Pier Vincenzo Mengaldo. For the English-speaking public, the work of reference is Steven Botterill's 1996 edition, which draws exclusively on Mengaldo's edition. But while Mengaldo draws from several manuscripts after a decades-long process of researching and studying the DVE's manuscript tradition, Botterill only considers the Latin text established by Mengaldo (and, from what I can tell, his Italian translation!). Is this acceptable?

Another interesting case is that of Dante's Rime, the posthumous collection of lyrics which were never included in an "official" work (like the Convivio, the Fiore, or the Vita Nuova), and never divulged together, as one work, by the author (unlike, for example, Petrarch's Canzoniere). For most of the 20th century, the Rime circulated in several editions, which differed from one another but only marginally (most accepted the ordering of the poems which had established itself throughout the centuries, and included as an appendix the "rime dubbie", those of uncertain attribution). A couple of years ago, leading dantist Domenico De Robertis published the crowning work of his long career, a new critical edition of the Rime which radically subverts the previously established order of the poems, definitively attributes to Dante several of the "rime dubbie" while ousting others which had long been attributed to him, and operates many changes in the accepted spelling. De Robertis' latest edition almost instantly established itself as the work of reference among Dante scholars. However, a non-Italian-speaking reader, as of now, has no access to it, as neither the whole work nor the 300-page introduction have been translated into English (nor, as far as I know, in any other language).... Furthermore, is it possible to simply "translate" a critical edition of a work? Wouldn't anyone embarking in such a task (you'd assume he/she would also be an authority in the field) inevitably come across certain things he/she wouldn't agree with? Can you have a critical edition of a critical edition? (perhaps it would be useful, but poetry itself is so unappealing to publishers, because of its extremely low mass appeal and profitability...)