Seniors represent a growing user base for mobile applications; however, many apps fail to adequately address their accessibility challenges and usability preferences. To investigate this issue, we conducted an exploratory focus group study with 16 senior participants, from which we derived an initial set of user personas highlighting key accessibility and personalisation barriers. These personas informed the development of a model-driven engineering toolset, which was used to generate adaptive mobile app prototypes tailored to seniors' needs. We then conducted a second focus group study with 22 seniors to evaluate these prototypes and validate our findings. Based on insights from both studies, we developed a refined set of personas and a series of accessibility and personalisation recommendations grounded in empirical data, prior research, accessibility standards, and developer resources, aimed at supporting software practitioners in designing more inclusive mobile applications.