I'm confused, what do you mean by Fantasyland 3.0? Because Fantasyland never got NFL'ed, outside of updating environments and attractions to be more modern in the 80's.
(what I say next, are speculative and isn't with a knowing eye)
..Odds are, NFL will start after Marvel & DCA or the possible Runaway Railway port. It would make sense, especially as construction materials are being spread out, with Inside Out, the Parking Expansion in the west, Marvel's First Phase, and Galaxy's Edge taking a lot from them as it is.
As far as guesses..one would think they'd look to what they are doing overseas, particularly Paris and Tokyo, with maybe the Mine Train from Orlando/Shanghai being looked at for some capacity. And Frozen, Tangled, and Beauty and The Beasts in their own way's; can make money (and a lot of it depending on what IP it is).
Odd's are, if I was a guessing man..
- Frozen (Aerendale with a Dual-Load version of FEA and the HKDL Mine Train Coaster)
- Expanded Meet & Greet Hall for Princesses
- Gastons Village and Beast's Castle (A Toned Down version of what the Tokyo attraction is, with more screens & Be Our Guest)