I couldn't understand the uncle-and-the-bears thing. Some cultural reference that I am unfamiliar with, I suppose. But I would like to know about the subtext or whatever is going on there.
Highly intriguing, and I anticipate that it will be quite satisfying when it does fall into place.
The light-hearted meaning is that Uncle Walter is an eccentric, and his family accepts his whimsical behavior.
The darker meaning is that Uncle Walter goes out at night on a bender, getting drunk. He comes back drunk and disheveled the following day, so the parents tell the kids that Uncle Walter went Waltzing with Bears to explain his appearance benignly.