simple or progressive form?

Dear teachers,

Would you please tell me if we can use both forms in the following sentences or should we use the progressive form only?

1) John’s parents had met in Cologne, Germany after they had been living / had lived there for five years.

2) This year John has flown over 50,000 miles for his job. He has worked / has been working for Jackson & Co. for almost two years now.

3) John's parents met one day while his father was reading a book in the library and his mother was sitting / sat down beside him.

Thank you for your help.