@ blade: as i said arcanine is better all-around. it won't force switches, which are made bad by stealth rock. and arcanine can defend from sweepers and get past walls.
@ZLS: i would have thunderbolt, for double or multi battles.
also, how do you challenge frontier brains? idk how...
eh. I'll probably go with Thunderbolt, but I can always switch it back if I need to..
as for battling the FBs... each one requires a different method. i think these are correct:
Battle Castle: complete 20 single battles and fight the brain on the 21st.
Battle Hall: Complete 49 battles and fight the brain on the 50th.
Battle Tower: Complete 20 single battles and fight the brain on the 21st.
Battle Factory: Complete 20 single battles and fight the brain on the 21st.
idk about the last one... don't even know the name...
@DB: I have no idea which one. I would probably go with the first one, only because Torterra is physically based. The HP is a letdown though...