Default [Q] Can you partition EXT4 on internal card for moving apps to SD?

So my brother has had an HTC One S for a while now, and we're going to root it. However, I'm not finding information as to what options he has to move apps to his internal SD. Can you partition the internal to say, EXT4 or something of that nature to use one of the many app2sd apps?
Any info would be great!

First learned on: HTC Glacier: myTouch 4G
Sold on swappa:T-Mobile Samsung Galaxy S II T989 + SGS3 T999L LTE
Current: T-Mo LG G2 D801