Hey @g-bougard,
You did not miss something, this is the right place to move fw with your request.
If you take a look at our Process for reviewing classic confinement snaps, the need to launch arbitrary applications is not generally considered a supported use-case for classic confinement. Have you explore the possibility of shipping the tools you need (e.g. stage-package) in your snap?
You could also try the mount-observe interface and in this way keep your snap strictly confined, enjoying all the benefits of a stable runtime environment. Please remember that classic snaps run in the global mount namespace, which means great care must be taken for the snap to work reliably across distributions.