So excited for the extended demo! I'm sure it'll be awesome!
As for the final release date, don't sweat it - delays are not the end of the world, especially if it means staying in good health and delivering an even better game. I can wait, and I'm pretty sure we all can, so just keep having your priorities right as you seem to do so far, and you'll be fine!
I'm still very happy to have an update - it made my day!