The way to get what you want with group hiking is to run your own group! I've been doing this for a long time now. You can bet there are many people who want the same pacing and have been looking for that. Many groups now run on meetup.com, groupspaces, or if you ask around town I bet you there are small "home grown" groups as well. The folks who work at outdoor sporting good stores are the ones who refer folks to my group.

You absolutely do NOT have to be an expert to get people together and go backpacking. It does help immensely to all be on the same page - agree to the pacing and itinerary, and not to abandon anyone - you'd be surprised the conclusions people come to on the trail about this sort of thing.

Find a backpacking class and take it. They'll start you off slow and can be a good re-introduction to what's available.

Start looking at articles online and read books - there are legion.

re: the dog - already said my piece on that. In short, leave the weapons out of the picture, and take bear spray for the bears if hiking where grizzlies are. The rest is a matter of food storage and not being so afraid of other people. I have learned over time that not acting like a victim is the key to not being one. For that you have to believe you won't be one - self defense class, not a dog, is the best way.