Changing another blueprint's mesh?

I still can’t add anything to the default value of any BPObject variable in any blueprint. I thought that maybe it wasn’t letting me add anything because my player character isn’t technically in the world, but spawns at a player start. So I made a nightvisionBP, threw it in the level, added a “lazercolor” variable and gave it a bp object reference to “Lazer1”. But when I click on the variable “lazercolor” in my nightvisionBP I can’t change the default value to an actor in the scene (its greyed out)

Please keep in mind that this whole time I have had instances of “Lazer1” in the level (the first actor changes color when it is supposed to). It simply cannot be the reason why this isn’t working, I can play the game and see the 1 object changing.

This is the root of the issue, and if when I figure out how to fix it I will be in really good shape. I’m hanging in there and appreciate the help.

Edit: I am able to correctly reference blueprints the way you showed me in my level blueprint, but it continues not to work for me when going BP>BP.