Does sin and ransom (Fidyahh) always apply to any person who does a prohibited act during the state of Ihram?

We must inquire about the state of the wrongdoer and determine which of the
following scenarios he falls under:

1. First Scenario:

He does the prohibited act unintentionally either due to forgetfulness or lack of knowledge, in which case there is no sin on him and no sacrifice required. 

2. Second Scenario:

He did the prohibited act intentionally, but with an excuse that justifies his doing, such as an illness or cold weather, in which case there is no sin on him. However, he has to offer a sacrifice. 

3. Third Scenario:

He does the prohibited act intentionally without an excuse  in which case he is sinful and required to offer a sacrifice. He also has to turn too Allah for tawba and repentance for his wrongdoing.