Well, as my own concerns are being thought up, I cannot help but wonder these questions:
-Can 6-reborns [dojutsu/taijutsu] be reborn as well?
-Will the "forest" and "elite forest" both be visible or just one?
-Can't we make one forest like this: [elite forest]
You begin to ponder upon entering the forest, as you do so, several spine-tingling, blood curling screams emit from the forest, horrendous beasts growling and your mind begins to contemplate on these factors.
You quickly turn tail and away from the malevolent forest.
Or something along those lines.
They did some type of thing like this with orochimaru's hideout.
People under a certain number of dks cannot go in because they are "too weak".