There is a lot to say about the scope and main vision behind RE7, and why it had that selective amount of diversity within the enemies. From the beginning it was supposed be a more personal and intimate experience, focusing mainly on the pursuers inside the game. Takeuchi wanted to create a new level of interaction with the monsters you were trying to scape, making them relate to you in a twisted version of your reality. That's when the concept of "family" became the most important and focused part of the title, that's when the Bakers were created.
They would appeal to different kinds of horror, like Jack with the "slasher" genre (Jason Voorhees, Michael Myers or Jack Torrance), Marguerite focusing on body horror (just like The Fly and The Thing) and obviously Lucas trying to reference movies like Saw as well. It became clear that they were the main attraction of Resi 7, that's why i always say that the Baker familiy is basically the heart and soul of the game. But on the other hand, they needed some type of "front soldier" to keep the player doing things in a great sense of pacing, and to expand within the concept of the mold infection.
In earlier concepts, and the idea from the artist behind them, was to create uniform enemies that while were humanoid in a sense, would confuse the player in dark places, making them appear like shadows coming from nowhere. That's why they work in tight places with fewer light (like the basement or the second floor in the Old House), but unfortunately RE7 overused them in the worst ways possible, which is a shame.
Coming back to the topic of budget, development focus and scope, they were messing with a lot of ideas which they tried to implement within the title. But it's very difficult to predict what type of things will work inside the game and not only on paper, usually the first stage of any gaming production starts with a lot of amazing ideas and concepts, but later the reality smashed them down and they need to focus on specific things, to deliver the experience with the quality and amount of polish the developers are know for.
For an example, there was supposed to be a dog (like a pet) within the Baker family. Her name was Diane, and opposing the traditional usage of dog enemies within almost every RE games, it was supposed to be a unique foe just like the rest of the family, being a pursuer as well. Another interesting concept was zombies that would hear your breath while passing around you, so the player had to press a button to hold their breath with a limited amount of time. Both concepts were scrapped because of the tight scope behind Resident Evil 7 and player feedback as well (players would hold their breath in real life as well, making the game extremely stressful to play in longer sessions).
But if you want to know more about the development scenario of RE7, and why they had to cut several things during the later phases of production, give this post i made earlier a read:
