One way of looking at it, is to engage them in co-designing the app. Many will participate because they like the idea of being involved into a "cool" project that solves a common problem. The caveat is that you need to have a structured approach, have clear deliverables, and that not all of the "co-created" outcome is usable as turn-key solution; it needs to be analyzed in terms of what problems they want to solve and how (which are both key pillars of any strong consumer insight)
If you can get them for a couple of hours is a common space, it is going to be more efficient, but, if that is not possible, you can co-create on-line, by simply using a forum app, or even a Facebook closed group.
While co-creation is a very powerful tool, it also comes with a set of hurdles. The first challenge with co-creation - in general, regardless of whether it is on- or off-line - is to let enough time for actors to build a team dynamic, by working together, while at the same time, let their individualities come out in a way that is acceptable to other team members. A good portion of the co-creation effort is actually spent in building a working dynamic among all actors, before actually moving to pure co-creation. In this stage I tend to use tools and techniques from Design Thinking, which also help establishing an emotional connection to the scope of the project, as well as to other
team members (e.g., building Personas, Stakeholder Maps, Segmentations, Customer Journey,...).
The second challenge is setting up a decision-making mechanism, which is fair, efficient and does not generate frustration. In a physical session I would normally give
the chance to each participant to express three full votes (no fractions!) to other teams (not to their own work). In an on-line setting I usually reduce it to one vote, because otherwise the complexity grows rapidly.
The third challenge relates to remote co-creation: I do not suspect broadband being a problem with your target group, the core problem relates to the difficulty of remote communication with multiple actors are discussing on-line: a lot of people, willingly or not, troll other people on line; moreover, very often several sub-threads are formed
and communication is not always easy to manage (e.g., imagine a chat with 10 users, the derivative discussions among subgroups are often polarizing everybody’s
Despite that I think a co-creation session is a great way of generating insights, tap into your customers' creativity, while ensuring a unique a relevant set of insights