Is there a hadith stating that a muezzin receives the reward of those who pray, and that whoever repeats the adhan also receives a reward, and does one who repeats the adhan of the Grand Mosque in Mecca via television receive the reward of those who pray in the Grand Mosque?

The story mentioned was not reported, but there are hadiths that indicate some of what it contained:

Firstly, regarding the muezzin receiving a reward similar to that of those who prayed with him: A hadith with this meaning was reported from Al-Bara', which states: "Indeed, Allah and His angels send blessings upon the first row, and the muezzin's voice is forgiven, and everything wet and dry that hears him testifies for him, and he receives a reward similar to that of those who pray with him." There is a difference of opinion regarding the authenticity of this hadith. Al-Albani authenticated it, while Al-Arna'ut weakened the phrase "and he receives a reward similar to that of those who pray with him." What supports this hadith is that one who guides to good receives the reward of its doer. The meaning of the hadith is that whoever attends [the prayer] due to his adhan receives a reward for guiding them.

Secondly, regarding the one who says what the muezzin says receiving a reward similar to his: A hadith with this meaning was reported, but it is not authentic. Al-Haythami and Al-Albani weakened it. Assuming this hadith were authentic, it does not necessarily mean that the muezzin and the one repeating after him are equal in reward in every respect. Rather, "he has a reward just as the muezzin has a reward, and this does not necessitate their equality in quantity and quality."

Allah's bounty is vast, and whoever repeats the adhan has a great reward. As for asserting that he receives a reward similar to that of one who prayed in the Sacred Mosque, this depends on the authenticity of the hadith, and it has been established that there is discussion about it.