What does 有模有样 mean?
模 is mu2 (some people pronounce it as mo2, but that's incorrect in this instance)

模样 is a common word in Chinese means appearance, especially referring to one's look.

有模有样 means has the look.

In the first context, 有模有样 means vivid and seems-to-be-true. 

In the second context,  it means the cat has the look of Harry Porter by waring the Uniform.

Another 成语 with 模样 is
人模狗样.
It means something looks good from outside, but indeed is bad from inside.