I think using 3711 would push the beer a fair bit away from the Baltic porter style. The beer would likely ferment out much drier which would take away from the big rich nature of the Baltic porter. And the yeast character (both fruityness and the phenols that you are looking) for would be a bit out of style.
But if you're alright with that then you could go for it. In that case you should think of the beer as a baltic poter/dark saison hybrid so that your expectations closer match what the beer will be. Or if you just want a little bit of pepper in a baltic porter you can add a little bit of pepper.