They literally sell BB-8 toys that can roll around and say on the blog that the Olaf robot is coming to Disneyland Paris and special appearances at Disneyland Hong Kong.
R2D2 is an example of one that you can buy in the gift shop (for $20k!) that was promised to make it into the park but just comes out highly supervised, occasionally.
I know there’s BB-8 toys, but I’m talking about the version meant for the parks: https://youtu.be/RDgZjdZsc6g
Much like Olaf (and many before him… dinosaurs, WALL-E, talking characters, etc), it was implied he’d wander around the parks. But it tends to happen for a short amount of time, mostly for events, and fade away quickly. (The blog post even says that: Olaf will be part of a 15 minute temporary show, and then will visit Hong Kong).
Maybe I’m wrong, but I’ve seen this exact thing happen a dozen times over the past 20+ years. (And watch the video I posted if you want to see more!)