You could meet all your expectations (... and more), demolishing the least.
The main objective of the project is to preserve and make the most of the existing structure.
The current construction its made with a load-bearing wall structure, which should not have many openings to avoid weakening it.
Then, the interventions that had been made in the thick load-bearing walls and existing slabs, strongly consider the safety of the structure without the need to resort to reinforcements that can increase the cost
