No, you can't send any CHL player down the the AHL while their season is ongoing. They can be in either the CHL (WHL, OHL, or QMJHL) or the NHL and that's it. Once a player is in the CHL, they cannot return to the NHL until their season is done, unless it is an emergency call up (I don't know if these actually exist anymore, but they used to). Years back Marty Biron made his Sabres debut on an injury call up.
This rule is in place so that the junior leagues don't get raided of all their talent. Without it, every drafted player would wind up in the AHL right away and the junior league talent would be heavily diluted.
I assume the rule you're hearing about a two player limit is that the junior leagues only allow their teams to carry at most 2 non-North American players at any time. This is being mentioned because Quebec, the junior team that has his rights, already has two non-NA players on their roster.