Mild cognitive impairment (MCI) is an early stage of cognitive decline that significantly increases the risk of dementia, making early interventions crucial for maintaining cognitive health in older adults. Our research takes a co-design approach to understand, design, and evaluate how socially assistive robots and a virtual human can promote lifestyle changes for people with MCI (pwMCI), potentially improving their cognitive health. Through an iterative refinement process, we aim to develop adaptable, user-friendly, and sustainable technologies that foster long-term engagement across diverse settings. Ultimately, our goal is to improve cognitive health, quality of life, emotional well-being, and loneliness in pwMCI.