Singular	Plural
I will have been walking	we will have been walking
you will have been walking	you will have been walking
he/she/it will have been walking	they will have been walking

Singular	Plural
I will have been sleeping	we will have been sleeping
you will have been sleeping	you will have been sleeping
he/she/it will have been sleeping	they will have been sleeping

Singular	Plural
There is no future perfect progressive for the "to be" verb. "Will have been being" is expressed simply as "will have been": "By this time next year we will have been being on this committee for a decade."