STL House Model Adaptation for 3D Printing

Title: Prepare Existing STL House Model for 3D Printing – 12" Model

I already have an STL file of a house model and need an experienced 3D printing/CAD designer to prepare it for printing.

Requirements:
Scale the complete model to approximately 12 inches in overall size.
Split the house into practical, printable parts.
Add grooves/tabs or similar alignment features so the parts can be assembled accurately.
Make the roof removable. It should securely set in place but be easy to remove so the interior can be viewed.
Keep the existing design and details of the house.
Optimize the parts for FDM 3D printing and avoid unnecessary supports where possible.
Ensure all parts are clean, watertight/manifold, and ready for slicing and printing.
Deliverables:
Final STL files, separated into printable parts.
Removable roof with proper fit.
Assembly/alignment features between parts.
If possible, provide the editable CAD/source file as well.

I will provide the existing STL file and Jacob's design comment:

"Let's add nice grooves to join the parts please. Let's also make it so that the top is removable. It should set in place, but be easily removable so the inside can be viewed."

Please include examples of similar 3D-printable models or STL modifications you have completed.