Does an ORMIT™-OpenJava Oracle Forms migration lock us in? Does the migrated application depend on proprietary libraries?

No lock-in. The application is built on standard frameworks (React or Angular, Spring Boot or Node.js) and its own REST API. The RENAPS parts come with a perpetual licence and all their source code (see the source code), so your team can maintain and change the application without RENAPS. The only other licence is the React version's data grid licence (see the data grid licence).