I think it's quite possible. Dunno about E3 though. Lets look at some facts here.
- Switch is likely to be the no.1 platform in Japan in short order. It's going to blow past the PS4. JRPGs are biggest in well (duh) Japan.
- The game from the very beginning basically is stated to be not exclusive to the PS4. Why would you say "Play it first on PS4" ... the entire phrasing basically confirms you can "play it later .... somewhere else".
- Cloud Amiibo seemed completely random considering there is no version of FF7 on any Nintendo platform. Ryu Amiibo foreshadowed Ultra SF2 for Switch. I personally think Nintendo cut a deal for this game last year, and that's why Cloud is in Smash.
- Square-Enix's president just recently said in an interview he wants more Switch content, including more ports where possible.
- The game runs on Unreal Engine 4, an engine that scales very well to the Switch chipset. A recent article stated there are like 20+ Switch UE4 games in development in Japan alone.
- Square-Enix's other big JRPG is Dragon Quest XI ... which is coming to Switch, that also runs on (you guessed it) Unreal Engine 4.
- Another reliable poster at NeoGaf, Orgen, who leaked Pokemon Black 2 and White 2 has said "he's heard" of a Japanese Unreal Engine 4 based port coming to Switch that's going to create a thread that gets archived (meaning it's a thread that's going to create a legendary meltdown on NeoGaf). Final Fantasy VIIR would fit that bill, in fact I can't really think of many other ports that would.
They might have to make a custom version for the Switch, but I think it's possible.
