Omg same, minifigures and creatures are so great in this wave but Hogwarts buildings are just terrible :D
The problem is that if you want all the minifigures and Basilisk from Chamber of Secrets set it would cost maybe even $80 so in that case its really hard to decide if it wouldnt better to buy whole set, it depends if you find great deal. For example I found all minifigures from Burrow set just for $40 but that was only $100 set, this one is $140 and will have moulded Basilisk and potentionaly much better minifigures so the price might be twice as high. Forbbiden Corridor is really tricky as I can see that one somehow work with my 2018-2020 Hogwarts layout if I change roofs for dark grey. I expect that the trio minifigures will go for $3-4 each but the Fluffy is gonna be expansive (from $10 to $15). With the bathroom set I recommend you just buy that set because its so cheap that if you bought minifigures separately, you wouldnt save any money.