Yea, not many informations around yet, so we have to wait for patch notes.
PvP-Roulette will include both Frontlines, but not Wolfs Den. Thats for sure

My guess besides that:
ilvl of frontlines will not be increased. I think they will stick to 80 on old and new frontlines
ilvl100 Animal gear will probably be no longer rank restricted to allow newer players to catch up on pvp endgame.
Rank 46-50 will be added aswell with new ilvl120 gear
Capture the flag is the new frontlines mode