Well, if the planet is Earthlike ... and if they've got past the "small uninteresting blobs" stage ... then I guess what we would likely find are those things which have evolved several times on Earth, convergently. So, for example, besides all the gliders we have true flight evolving separately in insects, birds, bats, and pterodactyls. This demonstrates that flight is quite likely, so we'd expect it to happen on Earth II at least once.
Would you, could you, can "we", know how likely it is to get past that stage?
It's hard to say. It's happened one time out of one that we know of. Now if the planet had been chosen at random then I would say that on that basis we should think it likely --- it may be a small sample, but since it's all we have, we shouldn't ignore it for being small.
But in this case we have a biased sample. If life, or post-blobby-thing life, had only happened on one planet in the whole universe, than naturally any beings intelligent enough to be sitting around discussing the odds of it happening like we are would have to be living on that one planet.