Lia are you certain that is how invites pass down? In the past players have passed the travel award down but I'm not sure if invites can be passed down the placings at nationals in the same way. Not that it is likely to happen but if invites did pass down then it is possible that the 8th 9th or lower placed player at a nationals would get one of the nationals invites. My 2nd place invite from 2003/4 didn't pass down if I remember correctly.
It is certainly the case that Premiere ratings invites don't pass down the national placings.
There may be a special case made for worlds T4 invitees.
Nationals invites are awarded before rankings, so I expect them to pass down.
If a Nation gets 3 invites (like Denmark) they should be allowed to hand them out all 3 of them.
In the situation 1 of the top4 finishers already has an invite (obvious from Worlds) then the other 3 should be given away in the Denmark case to nr 1, 3, and 4.
For me it's simple, Nationals invites are handed out during Nationals. Starting by nr1 and down untill they are out of invites.
This had nothing to do with rankinginvites, those are awarded after all Nationals are done.
It also doesn't matter if an Invite (Nationals) winner isn't able to go, that invite is awarded.
But from my point of view for Denmark the invited normally given to Steffen F should pass down to the next player.
But that's my opinion.
Also in 2003/4 we didn't have any Worlds invite winners.