Hey Marge! I have a suggestion to make. I see that in your app, as well as in your current ingame plans, Hastwyck is gonna sit on a cliff overlooking the sea. While that's a valid location for a castle, I feel like in general, but in the area you are working at specifically, it's a bit of a overdone trope. Bandallon, Roxton and Uffering are all currently located on cliffs or spurs overlooking the sea, projects that are located one after the other going down the Reach's coast.
Castles of a cliff are indeed historical, but less common that what our server makes one think. They have one major flaw: cliffs erode, and the castle will come down with it. Looking at your current terra, it seems like Hastwyck's cliffs are pretty soft, which would make building at the edge of them a challenging endeavour, as well as a potential waste, given the short lifespan the building at its top will have. Ballandon shows this phenomenon: there's visible chunks of the castle missing at it's seaside, having sunk with the rock bellow some time before our server date.
Another thing to consider is the menace that sea attacks present. While it could seem that an area frequently under the constant pillaging of pirates or raiders would raise mighty defenses near the coast, in real life more often that not population flew inland while keeping and eye at the sea with watchtowers. Given that Hastwyck is sandwiched between two big coastal castles and its status as a minor house, I think it is likely that it is located more inland, since by itself it wouldn't be able to sustain a castle strong enough to protect those around it, and if needed the surrounding houses can ward off ironborn.
There's several routes you can take regarding this change. The castle could be located on a small natural hill, or on the lowland, perhaps even an artificial mound. It would be interesting to play with the challenge of having to raise a fortification on a terrain that's "unfavorable". Just like the castles at the Crownlands, located mostly on plains, Hastwyck could rely more on artifical defenses, forced by the lack of natural ones. If needed you can start your brainstorming with this wikipedia page about
Lowland Castles. It is worth pointing out that among the list of castles on this page those located at the sea or coast are mentioned as a possibility. While this is true the whole point of this post is to move away from that, so you can disregard that bit.
Given that house Hastwyck has no canon location, there's plenty of room to play with it, and obviously given that a redo was approved for it there's no need to keep any features of the old version (like the fact that it was located on a small rocky peninsula).