I think the 5.0 (and 3.5 EcoBoost) replaces the 4.6/5.4, and the 6.2 replaces the V10 and fills the shoes the old 5.4 2V S/C engine did in the pre-'04 F150s.

The GT500 will likely get a boosted version of the 5.0 instead of the 6.2.

Unless Ford comes up with a set of 4V cylinder heads for the 6.2, it won't be a viable replacement for the 5.4 4V S/C which already makes 540 HP in the GT500, and 550+ HP next year.