For Dottie, there was at least one scene (maybe more but I don't remember now) that can only be progressed if you give her your load AND don't milk her for several consecutive days, because it only happens when her boobs are big enough. Also there is the scene in the Bakery, which has yet enother riddiculous quirk - you have to start it and leave it be, not clicking anything. After a while people will start to come by, and only one of those seemingly random visits unlocks the whole scene.
And don't get me started on "Hot Day". Not only they also have scenes that need to be repeated many times, the chance of even getting the Hot Day is also random. So yes, this game is so fucking tedious.
You might have to progress her storyline before being allowed to give her outfits. I'm not sure about the other ones, but for example the Cow outfit was available to give near the very end of her content. This should work like with the family, there will be a certain time when you are able to talk to them and give them outfits.