Bill C-6 creates three new board levels: a five-member land use planning board in the Gwich'in and Sahtu settlement areas; a Mackenzie Valley land and water board, subject to the creation of additional panels which will have up to 17 members, including a five-member permanent regional panel in each of the settlement areas; and an eleven-member environmental impact review board for the entire Mackenzie Valley.
The Mackenzie Valley land and water board will always have at least 5 members at all times. 
They probably will but nothing is certain.  If something happens to one of the five they will need a replacement.
( z1 have-org-role :ARG0 ( z2 person :quant ( z3 at-least :op 5 ) ) :ARG1 ( z4 board :mod ( z5 land ) :mod ( z6 water ) :location ( z7 country-region :name ( z8 name :op "Mackenzie" :op "Valley" ) ) ) :ARG2 ( z9 member ) :time ( z10 always ) :time ( z11 time :mod ( z12 all ) ) )