The hadith are:
First hadith:
It was narrated from 'Ubadah bin Samit that the Messenger of Allah (ﷺ) ruled: “There should be neither harming nor reciprocating harm."
This is also stated in Ibn Majah, 2341 which is from Ibn Abbas.
Generally, Islamqa doesn't cite any da'if (weak) hadith. They stated this hadith in their website without any reference, while stating the ruling on smoking, what they usually don't do. However, it's found in the book of hadith.
But with regards to this hadith of both isnaad, Sunnah.com said,
Grade : Da'if (Darussalam)
So is there anyone who classed it as Sahih (authentic), and who are they? And who classed it as Da'if (weak)? And where?
Second hadith:
Abu Barzah Al-Aslami narrated that the Messenger of Allah (s.a.w) said: "The feet of the slave of Allah shall not move [on the Day of Judgement] until he is asked about five things: about his life and what he did with it, about his knowledge and what he did with it, about his wealth and how he earned it and where he spent it on, about his body and for what did he wear it out."
— Timidhi, English reference, Vol. 4, Book 11, Hadith 2417; Arabic reference, Book 37, Hadith 2602
This is the same case. Islamqa cited it in the same page mentioned above, without any reference what they usually don't do. However, it's also found in the book of hadith. And it's not only Islamqa who cites this hadith, rather I've listened the hadith from different places.
But Sunnah.com said,
Grade : Da'if (Darussalam)
— Timidhi, English reference, Vol. 4, Book 11, Hadith 2417; Arabic reference, Book 37, Hadith 2602
With regards to this hadith, my questions is same as the above. Is there anyone who classed it as Sahih (authentic), and who are they? And who classed it as Da'if (weak)? And where?
But the fact is, all of this differences is raised and dissimilarities are found when the grade of the hadith is by Darussalam. It's not the only place where such dissimilarities are seen, rather in many cases, I have observed the same thing when the grade is by Darussalam.
Sometimes I feel it, unreliable to rely upon sunnah.com with regards to the grade of hadith, when it is by Darussalam.
Because, the Hadith regarding Salatul Tasbih was classed as Sahih by Sunnah.com with the grade by Darussalam. But Islamqa proved it to be wrong in here and here.
And there are many incident like this that made the grade of hadith declared by sunnah.com with the reference of Darussalam, disputed, I think.
So it's requested to answer the questions with reliable references.