Yes, but only if a request for entry is filed within one month before the deadline (i.e. between 30 and 31 months from the earliest priority date). Late submission is allowed at additional cost, but only up to one month from the deadline.
The notice of acceptance (not a notice of allowance) is issued after whichever comes earlier between (1) the end of the 31-month period from the earliest priority date and (2) the date of the request for examination.
To update the application record, you may either submit the PCT/IB/306 form for changing the record of the application or provide an assignment document that is duly notarized and translated into English.
Unfortunately, no. The Korean Intellectual Property Office does not allow for the restoration of the right of priority under PCT Rule 26bis. As a result, the international filing date must be within one year from the earliest priority date, taking into account weekends and holidays as exceptions.
The deadline for entry is 31 months from the earliest priority date of the PCT application.