The early mornings can certainly become wearing
I remember sitting on the floor in the extension when Maggie was a baby and crying - I was just finding getting up at 5 every morning a tad much! And bless her, she was great overnight - but about 5 she decided well that was the time to get up... so I'd get up, let her out and then we'd have a little play before I started to doze on the sofa and she'd settle down with me till about 7. She was never great at being left alone either but got their eventually. Doogle really is just a baby, you know that yourself, and they all learn at different rates and at the moment he's really just a baby waking early each day....
Have to say the only way I got to sleep in was after Maggie was really ill at about 6 months, and I took her upstairs with me and she slept through till whenever I woke up. Not suggesting you need to do that at all - more that at 14 weeks maybe you're expecting him to understand too much whats expected from him. Karma's way of pushing the time back to get up sounds really good - definitely worth a go. Maybe try feeding him his breakfast in a kong in his crate?
Again - re the stones in the bottle.... this was a method I had to watch my parents battling their gobby GSD with for many years, and if it wasn't so sad it was almost comical watching them both building up into a crescendo... dog barking, one rattle.... dog barking, couple of sharp rattles... momentary lapse of "YAY! you've got you ratttle thing".... BARKING louder, rattling louder.... and on and on... until eventually the dog stopped. And it had nothing to do with the rattling, it was when she wanted to. But for my mind, it heightened her whole sense of edginess which is what made her bark in the first place. Counterproductive - but my folks just couldn't see it.
Hope you can find some methods that work for you and Doogle... he sounds a fab young fella