I'm totally kidding, of course
A few thoughts:
- Your solutions should not be reliant on drag-and-drop, which is a bad mobile experience.
- Your solution should reflect a traditional messaging app, which is an existing and familiar paradigm.
A Very Rough Solution...
...That May Not Be the Right One
It sounds like you're likely not coming from a background of UX experience, but you're beginning to understand the value of usability, especially for a new app. I know your resources are limited, but it would be very well worth your time to look into hiring a UX professional (either as a full team member or paid consultant) to help you along the way.
This design likely works, in a vacuum. The biggest problem, however, is that applications are never used in a vacuum. Your users will come with their own set of biases, accessibility issues, preferences, and experience that could drastically influence the design.
I don't know enough about your architecture, development skills, environment, users, personas, use cases, and journeys to say whether or not this is a viable (or even useful) design. This is where a UX professional with research skills would come in tremendously handy-- in both helping you set your target audience and key metrics that will guide your overall design strategy. From there you'll need someone with experience designing for those groups and metrics, or at least an understanding of the core concepts necessary to optimize the design to these needs.
If you can't afford a paid UXer, ask around here, consider making the project open-source.
Keep in mind, though, that you get what you pay for. While I'm always quick to suggest that new UXers get experience by working on open-source projects, I always caution them against giving away their work for free. We are professionals with a very specific skill set, and deserve to compensated as such. While your project is in its open-source infancy, it's not likely to attract more skilled pros looking for a challenge.
I hope that's helpful. As always, please let me know if you have any questions.