Are the pledge documents and contracts of Daqiao Company legal?

Illegal.

According to Baidu law, according to Article 15 of the Resident Identity Card Law, no organization or individual may seize a resident identity card.

Legal basis: Article 15 of the Law of the People's Republic of China on Resident Identity Cards. No organization or individual may detain a resident identity card. Sixteenth of the illegal seizure of identity cards, given a warning by the public security organs, and impose a fine of 200 yuan.