The way I read the propsal is -
There is one vote on three parts, not three seperate votes on each section. So, part 1 admit Sevco to the SFL, part 2 agree that they will play in SFL3 and part 3 agree that either Dundee or Dunfermline will go to the SPL.
The massive rider on part 2 is they go to SFL3
Presumably the SFL board have already agreed their measures with the SPL and SFA, so when the clubs vote yes to part 1 and automatically vote yes to parts 2 and 3 the board then announce that they have an agreement with the SPL and SFA therefore Sevco will go directly to SFL1.
The only way round it is if enough clubs have the balls to vote NO which I guess is not likely.