You don't have to be 20. The original poster is correct and you're wrong. Nikita Filatov played in the ahl last year as an 18 year old. Age has nothing to do with it and it's all about whether a chl team has a player under contract and that's when they have to be 20 to play in the ahl. The rule is in place to protect the chl, so all nhl teams don't stash all the chl's star players in the ahl with no intention of using them in the nhl. All chl players can go to the ahl once their team's season is completed, which is why hodgson was allowed to play in the ahl this year.
Everett does own jordan's rights, however, I'm not sure if he would be forced to go there if he left minny and didn't make the nhl or cause he has no contract with them, if he could bypass them and go to the ahl. I'd have to look that up. My initial guess is that he could go to the ahl cause a chl team had filatov's rights last year and he could have gone either to the chl or ahl and columbus chose the ahl for him.