The entire link system is backwards. The arbitrary restrictions in place, simply don't need to be there.
What purpose do they serve other than to inhibit the player?
1) Why can only 1 character at a time benefit from the bonuses?
-Considering we can re-assign all link skills to any character of our choosing, this is a useless restriction.
-We can only play on one character at any given time regardless.
-This restriction is not beneficial to game-play in any way.
2) Why is there a "once per day" limit to linking the bonuses to other characters?
-Adds a waiting period to restriction 1, which makes the system even more tedious to use.
-Again, the restriction is not beneficial to game-play in any way.
My suggestion is to abolish the link system entirely and change all link skills into beginner skills that passively level up when the relevant characters reach certain levels.
"Blessing of the Fairy" and "Blessing of Cygnus" are perfect examples of how these skills can be implemented across all characters without the need for the link system.
On a separate note, "Blessing of the Fairy" and "Blessing of Cygnus", should also be adjusted so that they stack with each other.
Being rewarded, at most, with an extra +25 weapon attack for having a level 250 character is not something that needs limiting either.