I'm a little confused at what the problem behaviors are and how you're been working on them?
From what I can gather these are the problems you have with her:
- It seems like there's some resource guarding happening with her toys, bed and cage? I'm getting that from the line: "She's very shy usually and always has been. Except when she's snarling like a wild wolf showing every tooth she has when she has toys, in her bed or cage"
-From the description "When we first got her she snapped at 3-4 people at my home all who were bending over by a table, desk or anything she might be under. She also quickly apologizes and will kiss after snapping!!" it seems like she's easily intimidated by people's body language but will recover quickly if they adopt a less 'threaning' posture (ie, go from bending over her- which for a dog, especially a small one, can be seen as a threatening/tense posture- to standing up straight or crouching next to her).
- She also seems to have trouble being locked in her crate.
- She's very fearful of other dogs/by your judgement doesn't have any idea how to interact with them
From the sound of it, she's a very shy, timid dog with very little confidence that was perhaps not given proper socialization as a young dog and/or may have inherited a less stable/more shy temperament from her parents (to my knowledge this is a problem in a lot of sheltie lines).
I would echo the above- in what ways have you been working with her on these things?
Also, what is your training goal with these behaviors? All dogs learn and recover at their own pace and I think it's important not to put a time constraint on this kind of training but I also think it's important and helpful to have goals, especially incremental goals.
I think its always a good idea to find a professional in your area who uses only positive reinforcement methods (especially in this case, this is not a dog I would want to expose to any corrections or harsh training) to work in person with on these behaviors. Even if you only have one or two training sessions with someone it can be a really good jumping off point- people here can be helpful and knowledgeable but it's always nice to have someone in person to critique the way you work with your dog, especially if you don't have much training experience or if the experience you have is with more confidant dogs or focused in obedience.
Here's how I would start to work on these things:
- I'll let someone else tackle the resource guarding as it's not something I've ever had to deal with.
- For her issues with body posture, I'd grab a clicker and some high value treats and work to desensitize her to what she sees as scary body posture. If you don't use clicker training you'll have to 'prime' the clicker first- essentially you click, treat, click, treat, etc (I usually click 10 times) several times throughout the day for a few days- eventually she'll realize clicking always means she's going to get a treat. Then work on bending over her, clicking for her being relaxed, and giving her a treat. Eventually maybe ask others to help, work her up to a point where she realizes it's not scary after all.
- For crating issues, go back to basics on crate training. Leave her for 1 minute, then 2, then 3. Work your way up slowly.
- On her fear with other dogs I would suggest deciding exactly what it is that you want from her. She doesn't sound like she will ever be a real dog park dog. Does she lunge at walks and you want her to stop that? Or perhaps just growls when they pass by and you don't want her to do that? Are you actually wanting her to learn social skills and engage with other dogs? If you want her not to react to other dogs that can be achieved using treats to make the appearance of dogs always mean food. If you want her to play with dogs that's a different thing and maybe something to think about employing a professional to help you with.