A couple of ideas for the Iblis Sonic AU:
Amy babysits Cream in her spare time. When Vanilla was told that Amy got a new dog named "Beepy" she was expecting something like a chihuahua or pomeranian, not a multi-ton steel machine full of fire. Beepy is still a good boy tho.
The EN-100 series (Aka the AUs version of the E-100 robots) are named after the Latin alphabet, with there being 26 total (A-Z/100-125) and having codenames based on the NATO Phonetic Alphabet (Alpha, Bravo, Charlie, etc).
Eggman Nega uses animals as both a power source and their brains as biomechanical supercomputers. Not all of his machines do this, but it's almost impossible to tell which ones do without cracking them open.
After Onega gets seriously damaged, the main component left is a mysterious egg shaped pod, seemingly the main core of his entire body. It's opened up to reveal that it's actually a stasis pod for a red bearded vulture. Everyone is shocked at the revelation, but none are more shocked than EN-114 "Oscar" aka "Onega" himself. In hindsight, there were a few signs of Vulture-like behavior but with his vampiric design they didn't stand out.
He's lived his entire life as a massive, powerful machine, so all of a sudden waking up in the body of a perfectly normal bird was more than a little surprising. The worst part is that his "allies" were hesitant to restore his body! All sorts of ethical concerns like "We can't just recapture the bird, even if we'll miss Onega." Which was quite frankly just insulting. After giving Tails a piece of his mind, (using his beak and talons) it was blatantly obvious that the Vulture was indeed Onega's mind and was more than happy controlling a giant killing machine.
While Onega's body was being rebuilt, he was stuck as Shadow and Rouge's "pet vulture", Oscar.
EN-100 "Alpha" was sent to attack Amy Rose but with her blindness she mistook him for Boiling Point and gave it the same affection she usually gives him. The canine hardware in it's head never stood a chance of loyalty after being pet and called a good boy.
EN-101 "Bravo" was the most promising of the initial wave of EN-100 badniks, defeating it's "brothers" in combat (except for the original Alpha prototype) it was sent on several other missions where it out performed them again and again. Once Alpha went rogue Bravo was upgraded to take him out. They fought each other till the very end, when their wreckage was one smoldering pile, and two wolves emerged victorious. The brothers were eventually released back into the wild, free for the rest of their lives.
The broken bodies of Alpha and Bravo would eventually find themselves pulled into a place outside of conventional space and time. A planet where all the forgotten machines of a man who shouldn't exist go to rust away. The scrapniks on that planet would rebuild them to the best of their ability, resulting in a single robot they named "AB" or "Abby"
