Hello, no problem, happy to answer your questions!
- There is rarely direct influence between what you do in diplomacy and the main story (no you did X so Y happens in the main story), but at some key moment if a country like you they will help, if they dislike you they will make it harder for you and some decision might have further consequence on the long term (like epilogue wise).
- They are hard to get in a sense you need to do several precise bad decision to get their bad ending. For Alexander it's "the end justifies the mean" mentality, for Theodore is to put your well being before your country prosperity, and for Asha it's to not respect her.
Stupid decision are more likely to give a direct game over, so you can just reload and try again.
- No this choice with Asha is just about setting your boundaries! She will respect it either way, and you can romance any love interest! Overall simple shape choices (as opposed to the big choice screen) are here to set your MC personality and are "not important" to the story = unlikely to have big consequences.
- If you already know which love interest you will romance, you can spend all your time with them to not miss any content from them, I think it will be more enjoyable.
- Yes, you have unique choices (most of the time more favorable) depending of your starting specialty, as well as two unique scenes to really showcase your skill.
- No Calidya can't have two empress, but you can have an exclusive relationship with Asha. She will also have a route in a mariage DLC we will do later. There is a lot of possible relationship variation, but it's often open secret flavor. Most obvious, being: everybody know you are a couple, because you don't hide how close you are and you never marry etc. but officially everyone will pretend they don't see you kiss and say you are very good friend.
I hope it helps <3
Ayael