You *will* have vanilla scented soap, it will also discolor because of the vanilla itelf. Also the black specks (like what you see in premium vanilla ice cream) are not from the bean, but the seeds on the inside. They split the bean and scrape the seeds out. If you were to use it you would need to mix the seeds in with your oil to get the to separate. The seeds come out in a glob and it dropped into MP might not fully separate, so put it into a little dish with your FO or EO and mix to try and break them up.
However I have never used vanilla beans in this way before. I simply watch too mch food network and I've seen how the seeds come out clumped up
But odds are you will have discolored soap, and it will be vanilla scented from those seeds.