Summary: Inclusive Design starts with including users. Sadly, the 5 user sample size does not scale to inclusion efforts. Hence, you will need to include more users. However, it is important that you do not include a token user from an underrepresented community (eg. one wheelchair user). Instead, take an intersectional approach to user recruiting (eg. a wheelchair users who is Trans and Black). Finally, make sure to dedicate your audience research to full inclusiveness (versus adding a couple of users to check the inclusive box), so that you might understand the depth of experience for that impacted community and the issues that you need to know about to avoid bias, harm or exclusion in your product.
The shift toward Inclusive Design sees us adding more representation to visual search results, product strategy, and more (see Nike inclusive sizing below).