Pakistan was able to get Iranians the best possible deal in that MoU. Everyone, after reading the text of the MoU, would be of the opinion that Iran was the winner. The shit in Iranian skull interpreted it as the defeat for the US and a need for Pakistan. Neither of these is true. In addition, some/major elements in Iran didn't like the enormous increase in Pakistan global stature either.
Pakistan did all this mediation to save the region from devastation that Zionists planned for igniting a war between Shai and Sunni Muslims. Luckily that devastation is not in the interest of the US and China either. Iranians on the other hand tried every possible tactic for that war to break-out by launching missile and drone attacks on almost every Arab country, and foolishly so, including Qatar and Oman too. The world must admire Pakistan's efforts for prevailing on Arabs for not retaliating those attacks and appreciate Saudis for understanding and restraining.
China would certainly like the region not dragged into further turmoil. However, Chinese are unlikely to intervene in the war in Iran's support. Not at all. Chine's only strategic interest in Iran is to keep its oil inflow uninterrupted. Other than that, Iran has no strategic significance for Chine. If Straight of Hormuz gets closed due to Iranian stupidity and arrogance, that will not go smoothly with Chinese either.