Re: Does this neck cavity look correct??
Looks fine to me. Those who make/sell counterfeit Jems over the internet wouldn't bother going to this level of detail, particularly with the stamp in the neck pocket. In order to keep the price down, they'll skimp on various things, one of the biggest give-aways usually being the trem (a new Edge or Lo Pro costs just about as much one counterfeit axe).
Also, the trem checks out for 2010 and later Ė*the Edge was reintroduced on Jems, JSs etc. in 2010 and since then it doesn't bear the 'licensed under Floyd Rose patents' script on the whaletail because the whaletail patent Floyd (the man) held run out in the meantime.
Decal placement (and size) does vary subtly on guitars over the years too. Have seen plenty where the 'I' in Ibanez is almost touching the D string tuner bushing.