Let’ see if I can sum this up, as much for myself as anyone else based on what’s already posted and what I’ve seen in the past.
50 man protected list includes rostered/signed players as well as any unsigned prospects/players the team wishes to protect. Any unprotected players become FAs.
Anyone signed to a B/affiliate card can play 10 games without having to be signed to an A card plus any international events they can be called up for without counting those games towards the 10 game limit within certain dates on the schedule.
Any A carded players can play full time on the regular roster.
The team is allowed to dress 4 16 year olds per game regardless of what type of card they are on with any above limits taken into account.
The team may dress 3 OAs for any game while being allowed to carry more than 4 until November (not sure of the exact date) and then 3 as of the day prior to the trade deadline.
The team may dress 2 Imports for any game. If any of their Imports or those they hold the rights to are NHL picks they can draft/protect the rights to more than 2 but if they have 3 or 4 under their control they must move through trade or waiver any above two that are considered active on their roster.
What I am not sure about are the floating cards that come into play at the beginning of the season where teams can sign a player to a card that does not count towards the total A cards for the year while players are away at NHL or other pro camps. I believe this tends to be used when carrying more than 3 OAs at the start of the season as well as bubble players who won't likely earn a full time roster spot once any players away at camps are returned.
Teams can only use a total of 30 A cards for the year. Once a card has been used by a team that card is no longer available and does not transfer with the player, if traded to any other team. To acquire a player in a trade a team must have an available A card, if the player will be rostered or space on the 50 man protected list if they will be playing with an affiliate or the team is simply acquiring that player’s rights. You cannot acquire a player already signed to an A card on one team if you don’t have your own available A card to sign them to. I believe this is the trouble London ran into last year at the deadline with too many A cards used and no cards left at the deadline to make any more acquisitions through trades or sign anyone to an A card from within their system.
All rosters must be finalized by February (not sure of the date but I believe sometime in the first 10 days).
If a player is to be returned by their NHL team after the trade deadline the team receiving the player must have an A card available to roster the player as well as a spot on their 50 man protected list. This is what happened with Dale Mitchell in his last year as an OA in Windsor.
FAs initially signed to an A card, sent to an affiliate team then recalled by the team must be signed to a second A card. Windsor had this with Mario Culina in his first year in Windsor, signed, moved for playing time then recalled. I believe this only applies to FAs. If a drafted player is signed to an A card, sent to an affiliate then recalled I believe the original A card remains active as the issue is whether the player is signed and the card designation has no relevance. I think this prevents teams from attempting to hoard or block FAs if they have no intention of using them full time when another team may have offered them a full time position.
I think that covers the majority of it, someone correct what I may have wrong.