What what about Bubbles? You're welcome to use the name if you want, it's not copyrighted and I would be honoured rather than miffed, but I don't think your prospective new cat looks like a Bubbles - though he looks even less like a Goblin. Or do you mean how did she and Oscar interact? Well, mostly he leaped at her shouting "let's you and me wrastle" (not in English, obviously) and she would go "Eep!" and bat him on the nose before fleeing under the furniture.
They were both black and white DSH, Oscar being around twice the size of Bubbles, one of those force-of-nature cats who leaped fences in a single bound, sort of thing, and ate anything that didn't move faster than him (including Bubbles's dinner), while she was little and fussy and cuddly. They occasionally sat near each other in, not exactly friendship, but toleration, and even more rarely teamed up to chase strange cats away. Eventually he got epilepsy and then kidney disease, poor boy, so he was quiet and flat, which she liked much better. When he had to be PTS she was ecstatic. All the attention! Meals in peace!
Alas, she didn't get to enjoy being an only cat for long; she died of heart failure only a few months later, during a bout of hideously hot weather, at the age of 10. I was devastated and took the solemn oath not to make myself so emotionally vulnerable again. Gave all the cat gubbins away. It was nearly 5 years before I realised that my home (and heart) was missing a Very Important Ingredient. Hence, Thrifty and Izzy.