I'm not sure where you're going with this, unless you are personifying a family of dogs, but let's start at the beginning:
"So, once you are ready with your delicious dishes, then, let your family and friends ..."
The way you originally wrote it ("So, once you are ready with your delicious dishes."), that opening phrase was not a proper, complete sentence; therefore, it required a comma, to allow it to run into the actual complete sentence, with subject (implied YOU) and verb (LET).
And as for the rest of it, as I said, I'm not sure what you mean here, so I'll pass this off to someone else.
Student or Learner