Including children with communication disorders in the participatory design and evaluation of digital technologies is challenging, as communication between designers and users - an important part of this approach - can be impacted. Using Participatory Design with Proxies (PDwP) supports the inclusion of input from different stakeholders, such as parents, teachers and Speech-Language Pathologists (SLPs), who can provide valuable insight and feedback to augment direct input from users, which may be severely limited. We describe how we used PDwP to design a digital living media system that motivates children with disabilities to use digital therapeutic and learning applications and supports communication and collaboration between users. We employed an iterative design process to fabricate three functional prototypes and used them as design probes in participants' home and school settings. We present lessons learned in the form of the strengths and shortcomings of using PDwP for designing systems for children with limited communication abilities.