Please find response to question, I hope it will be helpful for you.

1. You may visit Gharaffa Immigration office with documents and they will change it on spot. (Bring all documents photo copies with you, You passport, Visa, Visa holder passport..... just in case).
2. Not sure about wakra
3. Few seconds (If all other information are correct in Visa, for example Passport number, Father name etc etc).
4. You family member might face some problems due to this mistake from thier origination airport.

Regards