I have not come across an official confirmation but based on all the money Pakistan is receiving from USA, it is highly likely that Pakistan will be used as a launchpad by USA against Iran. Thus, I would not be surprised if USA has started moving man and material to Pakistan. It is quite possible that some US assets were hit by Indian Air Force during Operation Sindhoor; I do not know. Eventually we will know. One thing is for sure, USA was not just hoping, it was casually sure that India would get hit by at least one Pakistanese nuclear bomb. USA did not expect that India would start bombing Pakistanese nuclear facilities. On the contrary, USA was expecting to put pressure on India using threats of Pakistanese nukes. However, once India started bombing Pakistanese nuclear facilities in the broad day light, US gamut to contain India fell apart.
China despite being a member of Troika supported Pakistan, initially. But as the conflict progressed, China realized that India was able to isolate Pakistan completely by jamming Chinese signals. At this point, China thought that it would be better to have India as a friend than enemy. So both India and China downplayed Chinese involvement in the conflict. Russians have been urging Chinese to mend fences with India; but China and USA thought, this was a great time to inflict wounds on India. This proved to be a big miscalculation.
As a side effect of Operation Sindhoor, for the first time, mainly after realizing India's military capabilities, Chinese are really sincerely interested in Troika.