Foreign Pension Reporting

My husband and I are US citizens, who each hold individual UK pensions.  I have a non-contributory defined benefit pension through my ex-employer, and my husband has a defined contribution pension currently with Aviva.  We have not received any distributions or payments so far.  This is the first time realizing we have a requirement to file anything related to our UK pensions.

What are our filing requirements related to these forms?
FBAR
Form 8938

Forms 3520/3520A
Do we need to file any delinquent forms for previous years, and if so, how many years do we have to go back?