All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is not a condition to implement the Hadd [a corporal punishment prescribed for crimes] for the repentance to be valid. Rather, if a person sincerely repents from a sin that necessitates Hadd, and returned the rights to their owners, in case the sin was related to the rights of the people, then his repentance is valid and he is acquitted from sin.
The evidence proving this is the narration which ‘Abdullaah ibn ‘Umar narrated in which the Prophet said: "Avoid these filthy things [sins] which Allah has forbidden, but if anyone commits any of them, then let him conceal that which Allah has concealed, and let him repent, for whoever discloses to us what he has done, we will carry out the punishment prescribed in the Book of Allah the Al-Mighty on him." [Al-Haakim and Al-Bayhaqi, and Al-Albaani classified it as authentic]
Al-Munaawi said: "It is obligatory on a Mukallaf [a person competent for religious assignment; i.e., reached puberty and is sane] who committed a sin that requires a Hadd, to conceal himself and repent. If he confesses his sin to the ruler, then the Hadd or Ta’zeer [a discretionary punishment] should be implemented on him.” [End of quote]
As far as we know, there is no scholar who conditioned the implementation of the Hadd for the repentance to be valid. The difference of opinion is about whether it is better to confess the sin to the ruler so that the Hadd will be implemented on him, like what Maa’iz and female companion from Al-Ghaamidi tribe did [they confessed their sin of Zina to the Prophet] or is it better that he repents between him and Allah?
This is not the place for analyzing which view is the most preponderant on this issue. Rather, it is enough to state that it is not a condition to implement the Hadd for the repentance to be valid.
Based on this, you would know the answer to what you have mentioned in the question, and that what the Shaykh whom you mentioned in your second question did was something good.
Again, as far as we know, there no scholar who conditioned the implementation of Hadd for the validity of the repentance. Therefore, it would have been better if you had attributed the statement to a specific scholar so that we could discuss it.
For more benefit on the definition of Hadd and Ta’zeer, please refer to Fatwa 366016.
Allah knows best.