diff --git a/src/bonsai/bonsai/bim/module/geometry/operator.py b/src/bonsai/bonsai/bim/module/geometry/operator.py
index 8d7b45883a..c28cbd37fb 100644
--- a/src/bonsai/bonsai/bim/module/geometry/operator.py
+++ b/src/bonsai/bonsai/bim/module/geometry/operator.py
@@ -878,8 +878,9 @@ class OverrideDelete(bpy.types.Operator):
         tool.Ifc.set(data["new_file"])
 
     def process_arrays(self, context: bpy.types.Context) -> None:
+        ifc_file = tool.Ifc.get()
         selected_objects = set(context.selected_objects)
-        array_parents = set()
+        array_parents: set[ifcopenshell.entity_instance] = set()
         for obj in context.selected_objects:
             element = tool.Ifc.get_entity(obj)
             if not element:
@@ -887,7 +888,7 @@ class OverrideDelete(bpy.types.Operator):
             pset = ifcopenshell.util.element.get_pset(element, "BBIM_Array")
             if not pset:
                 continue
-            array_parents.add(tool.Ifc.get().by_guid(pset["Parent"]))
+            array_parents.add(ifc_file.by_guid(pset["Parent"]))
 
         for array_parent in array_parents:
             array_parent_obj = tool.Ifc.get_object(array_parent)
@@ -923,8 +924,8 @@ class OverrideOutlinerDelete(bpy.types.Operator):
         if tool.Ifc.get():
             return IfcStore.execute_ifc_operator(self, context)
         # https://blender.stackexchange.com/questions/203729/python-get-selected-objects-in-outliner
-        objects_to_delete = set()
-        collections_to_delete = set()
+        objects_to_delete: set[bpy.types.Object] = set()
+        collections_to_delete: set[bpy.types.Collection] = set()
         for item in context.selected_ids:
             if item.bl_rna.identifier == "Collection":
                 collection = bpy.data.collections.get(item.name)
diff --git a/src/bonsai/bonsai/bim/module/style/operator.py b/src/bonsai/bonsai/bim/module/style/operator.py
index 12d1ca9f37..1a4f9b1f8f 100644
--- a/src/bonsai/bonsai/bim/module/style/operator.py
+++ b/src/bonsai/bonsai/bim/module/style/operator.py
@@ -740,6 +740,7 @@ class EnableEditingSurfaceStyle(bpy.types.Operator):
         if self.ifc_class == "IfcSurfaceStyleLighting":
 
             def callback(attribute_name, _, data):
+                assert attributes
                 color = attributes.add()
                 color.name = attribute_name
                 color_value = data[attribute_name]
diff --git a/src/bonsai/bonsai/tool/blender.py b/src/bonsai/bonsai/tool/blender.py
index cb7f05c844..1bcc6a7663 100644
--- a/src/bonsai/bonsai/tool/blender.py
+++ b/src/bonsai/bonsai/tool/blender.py
@@ -291,7 +291,7 @@ class Blender(bonsai.core.tool.Blender):
             return area.spaces.active
 
     @classmethod
-    def get_blender_prop_default_value(cls, props, prop_name: str) -> Any:
+    def get_blender_prop_default_value(cls, props: bpy.types.bpy_struct, prop_name: str) -> Any:
         prop_bl_rna = props.bl_rna.properties[prop_name]
         if getattr(prop_bl_rna, "array_length", 0) > 0:
             prop_value = prop_bl_rna.default_array
diff --git a/src/bonsai/bonsai/tool/style.py b/src/bonsai/bonsai/tool/style.py
index bf124e23a2..631f3b01f6 100644
--- a/src/bonsai/bonsai/tool/style.py
+++ b/src/bonsai/bonsai/tool/style.py
@@ -31,7 +31,8 @@ from mathutils import Color
 from typing import Union, Any, Optional, Literal, TYPE_CHECKING, Sequence
 
 if TYPE_CHECKING:
-    from bonsai.bim.module.style.prop import BIMStylesProperties, BIMStyleProperties
+    from bonsai.bim.prop import Attribute
+    from bonsai.bim.module.style.prop import BIMStylesProperties, BIMStyleProperties, ColourRgb
 
 # fmt: off
 TEXTURE_MAPS_BY_METHODS = {
@@ -516,7 +517,11 @@ class Style(bonsai.core.tool.Style):
         return results
 
     @classmethod
-    def get_style_ui_props_attributes(cls, style_type: str) -> Union[bpy.types.PropertyGroup, None]:
+    def get_style_ui_props_attributes(cls, style_type: str) -> Union[
+        bpy.types.bpy_prop_collection_idprop[Attribute],
+        bpy.types.bpy_prop_collection_idprop[ColourRgb],
+        None,
+    ]:
         props = tool.Style.get_style_props()
         if style_type == "IfcExternallyDefinedSurfaceStyle":
             return props.external_style_attributes