Hi Katrina,
Your post has given me hope for our little monster puppy! Really glad to hear Oscar is settling into family life.
Ivy isn't keen on her kibble either (Skinner's puppy chicken) and we also have to do the boiling water trick. I feed her 11am and 3pm kibble as training treats or in a puzzle, and squirt a bit of salmon oil on the kibble and mix it up in the measuring cup. It's enough to coat them a bit, make them smell amazing (to a puppy, absolutely not to me!), and soften them a little - but not so much that you can't handle them. She loves the stinky salmon oil so works like a charm, but it's a bit gross to handle and I have to wash the puzzles straight away after. Might work for Oscar too if he's keen on salmon?
Hope Oscar gets through the teething stage ok! Poor little thing. Always feel so sorry for babies when they're teething and you can see their pink cheeks. Glad it doesn't last as long in puppies!
Sophie x