Hi there! Absolutely great mod! I'm rebuilding entire base to replace Factorissimo's factories with your ones. And I've got some suggestions.
1. Occama's razor principle. IMHO it's not the best ieda to multiply the entities. I follow this principle in my mods (Teleportation, Blueprint Items Request). The idea is to add eact those items/recipes/entities you need. So it's sounds good to simplify the recipe of factory building to "steel + iron plates + concrete + stone bricks + etc" recalculated to your current recipes chain.
2. When you "teleport" the power, compare energy levels of outside and inside power interfaces and "fill" the lowest one. Didn't try it myself yet but sounds fine... Maybe we could turn on/off the power output (or even powerstation mode) by switching relay on the entrance (bottom) side of the factory (power pole appears/disappers outside, like chests/pipes do). So, you don't have to create new entities.