Yes, it was surely either two carriers, with random look (although the orange tabby siblings does prob gives us a hint of the parents looks). Here happened it to be two pointed, not just the statistical one of four. This is my guess.so would not be pure Siamese but she got the pointed gene from a siamese ancestor but it could be many generations in the past. From my understanding if both parents carry the point gene a pointed cat can be born.
So a slight update. I believe their eyecolour is actually getting lighter. Especially the small one. They are also getting distinct tabby patterns. Which confirms the two tabbies
found with them are true siblings.