The inheritance is what is speculative. Your parents are obligated to provide the dependency for which they were responsible. If someone kills your parents, they are obligated to you to provide for you as they would have been obligated. The obligation transfers. However, your parents were obligated to give you nothing after you reached adulthood, so if they’re land is stolen between the time you become an adult and the time they die, you have lost nothing. You didn’t own it. It wasn’t yours, and you had no more right to it than anyone else. You are viewing genetic relationships as if they make you into some kind of a collective, like you somehow already owned part of what your parents might or might not have left you. You are wrong. You lose nothing you have a right to, and can make no claim to it in the future.
No. It is actual, or there is no issue to discuss. If a parent retains the right of something that was taken form his possession, and explicitly wills it to a child, that child has the same claim the parent had. The problem we get into is when the inheritance is implied, and in that case, I agree, the claim of the child is severely and possibly fatally weakened.
That’s a legal construct based on tradition and custom. It’s not grounds for a moral principle. Bequeathment is a purposeful action, it can’t be assumed in a moral context, though it is legitimate for a legal system to use it as a default position in the absence of other substantive claims. What we are talking about here is most definitely not an absence of substantive competing claims.