Re: mounting issues
Gum arabic is extremely water soluble, of course, but otherwise should be fine. I've never used it as an adhesive so I can't speak to its adhesive properties.It is (or was) the glue used for stamps, envelopes and -obviously- gum-coated paper. I deem its water solubility an advantage, because if you need to detach the print all you need is to wet it and wait a little.
The drawback is that the print could bend after drying, and to contrast this you will need to glue another sheet to the back of the support.