If the handwriting is part of the art, every publisher will consider publishing a facsimile of a handwritten text.
An example is the work of Swiss artist Adolf Wölfli. Wölfli was a farm laborer suffering from a mental disorder, who started to create art while living in a psychiatric ward. His "writing" is interwoven with drawings and ornaments, and is published as facsimile, instead of typeset, because the special quality of his art would be lost. An example is his narrative Von der Wiege bis zum Graab.
The criterion by which publishers decide to publish a facsimile of a handwritten text is that the physical object of the paper with the writing on it is a piece of art and not simply a container of narrative. Narrative text can be rendered in any script and is not dependent on the handwriting. So a novel would certainly never be published in facsimile handwriting (except for scholars studying a famous writer and his writing process). But an artist's book will always be reproduced as facsimile.
As with any other type of publication, you have to find a suitable publisher and convince them.
Your questions (about multilingual and handwritten texts) seem to show that you have a view of writing, literature and reading that may be somewhat distinct from the bestseller market. Basically, as an answer to all your questions, there is a market for everything. There is a wide variety of non-standard books published by specialized publishers for a small and specialized readership. Some books have a print run of only a handful copies, and cost a fortune. But if you want to publish through a major publishing house and reach a large audience, you will have the best chance if your books look like any other book – though there are exceptions. But if you perceive of your work as art and find that it must be handwritten and in multiple languages, then that is how it must be, and all you need to do is resign yourself to being read by a small readership or not at all. The numbers of writers who created outstanding works but were never appreciated by the general public is legion. Bestsellers are not usually the greatest books. You must decide: Do you want to sell books? Or do you want to satisfy your own whims? Both is legitimate, but both paths lead to different outcomes.