Can't reference to other blueprints when exporting files

Hello!
I’m about to release a Spell System on the marketplace but i’m getting too many errors related to relations between blueprints when importing files into a new project.
Since a spell requires a caster to get info like enough mana to cast it, everytime i use it in a new project, i have to link them all again even if i have the same attributes on my character. This also happens with the projectile actor blueprint, i have to select it again in “spawn actor for class” node.
I guess that would deny me from putting it on the marketplace since people who buy it would spent some minutes on making it work.
So how can i avoid it?
Also can i include Starter Content’s assets into my package?
Sorry for my english :stuck_out_tongue: