Yeah, the game does recognize all heights from in CAS mode, but in the match they get "normalized" to a default value by the game in regular gameplay if they are outside a certain range. That said, one can still set a wider working range with Data Editor than what's selectable in the game. If I remember correctly, the working range for WWE 2k18 is 4'3" to 7'6" (I could be off a bit, since I can't find my testing notes on it, if you have more accurate values, feel free to refresh my memory). Data Editor displays the full foot range, since I've coded it to be calculated dynamically so it's easy to change via Settings file in case someone figures out how to unlock more ranges or if a new game has wider ranges available and it's easier to maintain and more accurate than the hard-coded values used in previous versions.
I haven't noticed 7'11" crashing the game for me during my testing (although it might also depend on the model you try the height on), but unexpected things can always happen if you set parameters unintended and untested by 2k (and in some cases even tested ones).