The time for wiping over socks may expire but your Wudu remains valid as long as you do not perform any act that breaks it.

There is no harm for a fasting person to taste food as needed. If they accidentally swallow it, there is no sin, and they can continue their fast.

Sujud Ash-Shukr is done in response to a calamity that is averted or a blessing which comes to a person. There is no specific du`a narrated in the hadiths for Sujud Ash-Shukr.

Your Sa`i between al-Safa and al-Marwah is valid, even if it was done without wudu because having wudu is not a condition of Sa`i.

There is no evidence to indicate that taking off leather slippers or socks that have been wiped over invalidates Wudu. If you wish to wipe over the socks again after breaking Wudu, you must perform a complete wudu, including washing your feet, before putting the socks back on.