As funny as it is, but no. And I'm not really sure this game even needs this. Yes, Cedar showed more interest in MC than a simple faithful sister would, but this is not really going anywhere for now, and mother is not even around frequent enough to build up any decent relationship, let alone intimate.
There is just too much of entertainment to happen even without this fetish. I'd lie if I say I'm against this to happen (with Cedar for sure), but not really too excited about this either. But I believe BD will do it right if he will be actually doing incest routes.