I guess this answers my question then. Building with static/stationary lights will not change anything since the geometry only gets brought into the scene after beginPlay, which means I will not be able to build the lighting for the geometry. Basically what I understand is if all the geometry has been constructed in the map (and not spawned programatically), even if they are dynamic mesh, I can use Modulated Shadows.
For now, I guess I’ll have to settle with dynamic directional light with as low as possible Dynamic Shadow Distance setting.
I will mark this question as answered now then since I assume I don’t have another alternative in the current state of the game.