From what I know, the raspberry Pi 2 has similar power to the 3DS and has an ARM processor.
Doubt it, although having an x86 processor means ps4 emulation is possible on PC's in the next 5-6 years, but there's a very low chance the ps5 will be more than double that of the ps4, let alone the standard x4 power requirement of emulators. Remember, emulators aren't running games, they run consoles that run games.