A good first step in designing any HyFlex course, as you recognized in your question, is to design a good quality online (asynchronous) course. If your institution is a member of Quality Matters or another organization that provides a certification process for verifying that an online course meets standards of good design, you could include the fee in your request. If training is allowed in the budget, these organizations have a number of courses that guide instructors in applying the standards to their course. Sorry, this advice likely comes well after the application deadline for your funding opportunity!