diff --git a/docs/changes/newsfragments/502.bugfix b/docs/changes/newsfragments/502.bugfix
new file mode 100644
index 000000000..f88e949df
--- /dev/null
+++ b/docs/changes/newsfragments/502.bugfix
@@ -0,0 +1 @@
+Fix type issues and update model configs for :class:`.BaseDataGrabber`, :class:`.BasePreprocessor`, :class:`.BaseMarker` and :class:`.BaseStorage` by `Synchon Mandal`_
diff --git a/junifer/datagrabber/base.py b/junifer/datagrabber/base.py
index c34fabdb5..4fb3796a6 100644
--- a/junifer/datagrabber/base.py
+++ b/junifer/datagrabber/base.py
@@ -13,7 +13,7 @@ from typing import Annotated, Any
 
 import structlog
 from aenum import Enum as AEnum
-from pydantic import BaseModel, BeforeValidator, ConfigDict, Field
+from pydantic import BaseModel, BeforeValidator, ConfigDict
 
 from ..pipeline import UpdateMetaMixin
 from ..typing import Element, Elements
@@ -58,11 +58,10 @@ class BaseDataGrabber(BaseModel, ABC, UpdateMetaMixin):
 
     """
 
-    model_config = ConfigDict(use_enum_values=True)
+    model_config = ConfigDict(extra="forbid", use_enum_values=True)
 
     types: Annotated[
         DataType | list[DataType],
-        Field(frozen=True),
         BeforeValidator(ensure_list),
     ]
     datadir: Path
diff --git a/junifer/markers/base.py b/junifer/markers/base.py
index be2ecba1c..06cb48fd8 100644
--- a/junifer/markers/base.py
+++ b/junifer/markers/base.py
@@ -6,16 +6,16 @@
 
 from abc import ABC, abstractmethod
 from copy import deepcopy
-from typing import Any, ClassVar
+from typing import Annotated, Any, ClassVar
 
 import structlog
-from pydantic import BaseModel, ConfigDict
+from pydantic import BaseModel, BeforeValidator, ConfigDict
 
 from ..datagrabber import DataType
 from ..pipeline import PipelineStepMixin, UpdateMetaMixin
 from ..storage import StorageType
 from ..typing import MarkerInOutMappings, StorageLike
-from ..utils import raise_error
+from ..utils import ensure_list_or_none, raise_error
 
 
 __all__ = ["BaseMarker"]
@@ -55,9 +55,12 @@ class BaseMarker(BaseModel, ABC, PipelineStepMixin, UpdateMetaMixin):
 
     _MARKER_INOUT_MAPPINGS: ClassVar[MarkerInOutMappings]
 
-    model_config = ConfigDict(use_enum_values=True)
+    model_config = ConfigDict(extra="forbid", use_enum_values=True)
 
-    on: list[DataType] | None = None
+    on: Annotated[
+        DataType | list[DataType] | None,
+        BeforeValidator(ensure_list_or_none),
+    ] = None
     name: str | None = None
 
     def model_post_init(self, context: Any):  # noqa: D102
diff --git a/junifer/preprocess/base.py b/junifer/preprocess/base.py
index fd84c38a5..6c3a41e41 100644
--- a/junifer/preprocess/base.py
+++ b/junifer/preprocess/base.py
@@ -55,7 +55,7 @@ class BasePreprocessor(BaseModel, ABC, PipelineStepMixin, UpdateMetaMixin):
 
     _VALID_DATA_TYPES: ClassVar[Sequence[DataType]]
 
-    model_config = ConfigDict(use_enum_values=True)
+    model_config = ConfigDict(extra="forbid", use_enum_values=True)
 
     on: Annotated[
         DataType | list[DataType] | None,
diff --git a/junifer/storage/base.py b/junifer/storage/base.py
index 2408cd0bf..a5c862db1 100644
--- a/junifer/storage/base.py
+++ b/junifer/storage/base.py
@@ -65,7 +65,9 @@ class BaseFeatureStorage(BaseModel, ABC):
 
     _STORAGE_TYPES: ClassVar[Sequence[StorageType]]
 
-    model_config = ConfigDict(frozen=True, use_enum_values=True)
+    model_config = ConfigDict(
+        extra="forbid", frozen=True, use_enum_values=True
+    )
 
     uri: Path
     single_output: bool = True