As Richard said, anything is possible on a plugin. What you’re proposing is likely a few hours work. There could be some shortcuts to take to fit your budget. Custom badges might also help. You could certainly get the new plugin written and then import the data to it when you do the migration.
Don’t mistake duplicating the old system for creating the best one.
You could use the solved plugin or tags to use way to turn off review time.
If your entire system is bespoke, a custom importer is typically on the order of $1500, and you’d likely need close to that much more for the needed plugin.