As per the CE rules preview. They are not counted in deck construction
at all. Everyone gets Border Keep regardless and only the player that
goes second will have the Bamboo Harvesters in play at all.
Would it be a code hassle to add a specific right-click menu option to
the Border Keep to allow it to create the Bamboo Harvesters card and
attach it to the play field? That way there won't be any logic in the
Egg itself to determine who needs to have the holding in play. The only
new code needed would be to add a menu option just to that card (not
sure if that's possible) and then link it to the other card spawning
methods that already exist.
-Bryan