That's an interesting point considering that both WPG and SJ could use this as a potential loophole.
Things still need to be ironed out in terms of what the protection limits will be. Right now it looks like 1 of 2 possibilities:
A) 3D, 7F, 1G
B) 8 skaters, 1G
However there has been other speculation that this number could be reduced slightly in attempt to improve the player pool available to the expansion team. I don't have exact number but it appears as though Buff and Burns both played very little at forward last year, making them Defencemen. I would anticipate that the NHL monitors their situations closely next year if expansion is happening and will inform the teams of what position eligibility they are. I think its safe to say both with fall under the D category.