For local usage on linux there's virt-manager, has been good enough for my use at least, and the integrated spice client has relatively good graphics performance for normal desktop use.
Edit: don't know about a good gui for running qemu on windows, though
There are different versions for interior and exterior use, using different types of glue. At least OSB/0 and OSB/1 can be used for internal applications and are considered safe. Not that I would trust a landlord doing this to select the correct board type, especially since the safe variants might have some issues with the humidity exposure in a kitchen.
But there still are many cases for using OSB indoors, e.g. behind drywall to give it some more strength (instead of more expensive plywood). Wouldn't want to leave it exposed in a kitchen though, it'll get messy if it's not properly treated, and in the picture it doesn't seem to be.