Sorry I've been really busy with guests here.
I honestly don't know about the leadership stuff.... he'll listen to us when we ask him 'leave it'. He'll wait to get his treats... he'll sit when he wants something... we've been doing that from the start.
I know the resource guarding thing started when he ended up destroying his plush toys and we took them away from him. He doesn't guard bones or the wood sticks he brings from outside etc... only the cloth stuff. He loves shoes too, but it's not a big deal to get them back. He'll drop them if we ask. We can be around him with cloth items, if one drops and he tries to grab it, we can get it back right away. If we ask him to leave it, he will. Sometimes someone forgets to put something away or to close a door and it's when he steals stuff really.
I usually just ignore him when he steals something, and I'm definitely not afraid of him, apart from that day because I was really exhausted, and I'm more scared about what could happen to the kids than anything else really... My husband is never afraid of him either. Boris just picks up very well when we're in a bad mood (which of course happens quite a bit more when you're sleep deprived). For example, the only time he bit my husband (and it wasn't that deep) is a day when he was in a really bad mood and yelled at him for stealing a tissue, then tried to get the tissue from his mouth. He totally deserved it...
Honestly if we're in normal moods he will be nervous if we get close to him when he stole something, but he usually won't growl.
I know I make it look like it's my husband's fault again, it just really doesn't make things easy... but again, he's not a moody freak or anything, he just gets easy to irritate when he's tired.