Dogs are some of the best indicators we have honestly. They pick up on frequencies we can't and when they lock onto a ceiling like that it's worth paying attention to.
Few questions - did the footsteps have any kind of rhythm or pattern to them, or was it more random shuffling? And roughly what time did this happen? I've been documenting cases like this for years and the 2-4am window comes up a lot more than coincidence would suggest.
Also were the dogs growling or just staring? That distinction matters to me. Growling usually points toward something they percieve as a threat. Silent staring is often something else entirely, something they're tracking rather than reacting to.
What's the roof situation like - pitched, flat? Any trees nearby? Not trying to rule out the mundane but if you've already checked for animals I'd love to hear more detail on what you actually heard up there.