I'm planning to join with a very specific character set-up...

[Kiri]

Oh I though this went without saying, but the ship did stop in ports before reaching the Souls territories.

Ah, yeah, I didn't make that assumption, but that makes the journey more reasonable for sure.

However, the sheep (and any other sort of livestock) probably wouldn't make it on a three month sea journey, even with restock stops. Feed for livestock takes up a lot more space than feed for Luperci, and grass/hay are prone to spoilage, especially in moist conditions. Fresh water storage would also be an issue. The amount of effort and resources needed to transport livestock overseas is generally not worth it, and it'd be much easier to acquire them via trade post-moorage.

See, my idea was that her two forms are a bit mutated but I understand if that's not allowed, I'll settle for regular beastly and anthro forms.

Pretty much all physical characteristics should be consistent across forms. You could have a Šarplaninac with long limbs, but they'd have them in Lupus form as well.

Btw, could a character's health be affected by changing forms? Like wounds sustained and healed in one form reopening when switching to another, or healed bones breaking again?

Physical wounds and ailments carry across forms and shifting might be prohibitively painful and/or aggravate wounds and injuries.

So correct, if a character say, obtains a knife wound on their shoulder in Optime form and it is lightly healed with a layer of fresh skin over it -- shifting to any other form could aggravate this wound and rip the layer of skin open again. However, once the wound is further along in the healing process and the new skin is more established, shifting should no longer cause significant new damage.

Similarly, broken bones are likely to hurt a LOT if a character tries to shift while they're freshly broken or only half-healed. Once they're fully healed though, shifting should not cause any new damage.

And would something like wobblers syndrome or various inherent disabilities carry over to other forms?

Yes, these would carry over as well. Blind in one form is blind in all forms, etc.

The only "exception" might be foreleg VS hindleg ailments or injuries. Having a limp in Lupus form due to an injured foreleg wouldn't carry over to a limp in Optime form since that foreleg would be an arm, but that arm would, of course, still have an injury -- it just doesn't impact their walking.