For the mk64fn1m0Vdc12 device, can you confirm if the VREFH is tied to VDDA in the 121 XBGA package? The datasheet ball out lists VREFH as a pin, so it implies it is not shorted to VDDA. Can you confirm?
Can I generally say if VDDA and VREFH are pinned out they are not connected internally. If I recall they are connected internally only on lower pin count parts.
If VREFH/VDDA are pinned out to a separate ball, then they would be separate. They are never tied together internally, they could be tied together in the package but that is generally only done for the 32-pin and smaller size packages.