https://www.baseball-reference.com/bullpen/Rule_5_Draft
http://manuals.ootpdevelopments.com/...e=rule_5_draft
Here are the best links to Rule 5 draft info if you have not read them.
But yeah that 17 yearold being eligible is weird. The only guys I've had taken from me are in AAA and (on 20-80 scale) with potential rated higher than 45-50. One I should have DFA'd a lower guy to get him on my 40-man roster. Another guy was released back to me before the season started.