So, I just received my confirmation email and it has a new key that works on steam. I'll leave this thread here in case anyone else has this experience. Maybe the rest of you simply knew or are more patient ;)
I just bought the upgrade for FE to upgrade to LH. When I try to activate it on steam, the serial on my purchases page in my Stardock account isn't recongnized. Do I need to wait for my email? I have to say I'm surprised I didn't receive an email after almost 8 hours (for most companies with digital purchases and steam activation it is virtually instant/automated).