In my experience, the interview process for jack of all trades job descriptions plays out the same way every time.

1.) The candidate shows up with a effectively all the required skills. Predictably, logically, the candidate has a roughly average level of skill across the range on average.

2.) The interviewers decide the candidate won't do because he/she is 'only' average in some area that should have been one entry on a short list of required skills in the first place.

Either hire for the skills you actually need and be specific about it or hire the smartest, hungriest people you can find and be honest about what they'll be expected to learn.