The first example is good. The second is correct, but unnecessarily wordy (the relative pronoun “that” can be omitted without loss of meaning). The third is incorrect; you need the “it” before “would.” One last option (and the most common in actual usage): you can omit everything after “predicted”: “The unemployment rate has risen much more than one would have predicted.” The “it would” clause does not really add or clarify any meaning that is not already there.

The first one is good. In the second sentance the last 'that' is redundant.