Well, you have 13.12 which deals with in-season transfers from and to Minor Leagues, and 13.10 defines Minor League:
13.10 Recognition of Minor League. For purposes of this Agreement, except as expressly set
forth in Article 9, Minor League club shall only include any club in the American Hockey
League.
(that exception from Article 9 being the ECHL for players on ELCs)
In-season transfers to and from other leagues simply aren't a thing, the one exception being the European Assignment clause.
Very good points there you got. The recalls seem to happen only from AHL.
But at the same time, CBA 11.19 explicitly talks of the duration of the Loan to AHL. Seems to be an iffy situation: either a) the Club can recall the EA clause player
as if he was in AHL, or b) the Club get a little bit screwed over if a player uses the EA clause because strictly speaking he can't be recalled according to CBA 13.10 and 13.12.
Technically Club does initially Loan the player to minor league, only after which the player can make himself be Loaned to league outside NA.
As per the definitions in CBA 1:
"Loan" means the transfer of a Player from a Club's Active Roster, Non-Roster, Injured Non-Roster or Injured Reserve List to the roster of a club outside the NHL.
Upin reconsideration I have to say that it is possible that NHL goes by the option b) and the Club can't recall a player who uses the EA clause.
KHL may be especially tricky because there is no transfer agreement between NHL and KHL. At the same time, EA clauses are used especially by Russians who don't feel like bussing around for 70k in AHL when they have the KHL option.