Yes, it is fragile (absence, breakdown, updates). We move them to a server, with scheduled runs, logs and alerts.
It is recommended for security and performance. Migration to a recent long-term support version is prepared with a dependency audit.
Not urgently if there is no problem, but it is advisable for a tool that must keep evolving for several years. The audit helps decide.
Yes, we prepare the listings, screenshots and submission. Developer accounts are created in your name.
React Native if you have a React ecosystem; Flutter for an identical look everywhere and a standalone mobile project.
To develop it, yes, and that is our job. To use and manage it, no.