I think it’s fantastic that you’re working on this transition out in the open here on meta. So many others will benefit from your experience.
I really want you to be successful too - as you know, I really need to join your community myself if you let me because of the four cats in my household that I need your help with! 
But I don’t ever want to have go back on facebook.
I think you are right though that you want to keep the facebook presence upright. If you are also present in other places you want to keep those active as well. Finding the balance is not going to be easy but it is possible.
Dave is reminding me that your helpers can be a big part of this. If enough of you are committed to hanging out every day on your Discourse site helping people and providing the things there that everyone needs, and you also are using only Discourse to communicate amongst yourselves, then your Discourse site will gain traction.