Here’s an idea for an online teaching methodology: Instead of starting and ending the class at specific dates, plan your course so that all materials, videos, text and exercises are ready in a protected web.
Then, offer starting dates at every 1st, 10th, and 20th of the month. This way, you will have various parallel running courses, and allow users the flexibility to start whenever they can.
As far as feedback goes, if you have a group chatroom, all students benefit — older students benefit from teaching the new ones and newer ones benefit from seeing what the older students have already accomplished.
And finally, to enrich even more the learning process, you can keep older student projects in a permanent gallery, so that newer students over time create even better results and learn from past students exercises.