While I would expected higher variance as the evolutionary gap increases, IMO the null hypothesis should be that their qualia are the same space as ours.

We're pre-paradigmatic for qualia, we don't know what structures (brain or otherwise) give rise to it in order to guess what set of qualia can be had by any given system. Until we do, I can't even quantify my expectations on the variance from increased evolutionary distance, I don't even have a quantity to express the variance of.

I feel like defaulting to not having the same is unjustified. Given that we have so much in common.

Defaulting to people having the same qualia is too much of a leap. You can't even begin to prove that your blue is my blue.