The rules I have are unfortunately very unclear in specifying whether shy animals are scared of omnivores. (They seem to specify that shy animals can't be placed in a cabin with an omnivore or a carnivore, nor in a cabin next to a carnivore.) From the rules available here, though, it seems that only carnivores matter.
Yes, the english rules are very clear on shy animals and omnivores:
Diagonal cabins are not a problem, nor do they have problems with omnivores.
Interesting that yours implies differently, it always makes you wonder what things get subtly changed when translating languages.