Pinkie-Dawn

You can only reach S-rank once. Once you reached S-rank with one character, the S will become darker for other units. So you're only able to marry someone once.

It gets hijacked by someone else before Grima hijacks it.

I wouldn't call it a ship really haha, I just randomly chose Maribelle. I plan to do a more serious run after I've collected all the supports though, which would mean pairing him with Olivia.

I have no idea, I never used healers since all I did was overgrind my characters.

I was just thinking of a username and it just popped in my mind I thought it sounded cute

Gaius is supposed to be good or something, idk about that since I don't play all that seriously at the moment.

You have to talk to him with Chrom iirc. I don't remember, you'll have to google it.

I'm not sure if this poses that much of a problem. We have "canon" designs for the Pokémon trainers, as can be seen on the scans of corocoro. I'm assuming they'll be using those in the next installment. Pokémon is one of the biggest franchises of Nintendo. It'd be a shame to leave them out of the next SSB.
The Avatar doesn't even have an official artwork (except with the hood on), that's why I think the designs for the trainers are more "canon" than the costumisations of your unit in FE.

And although I'm only half-way through FE:A, I don't see why Chrom isn't a main character. Maybe not the main character, but definitally a main character. He, or Lucina, might just as well be there to fight alongside his ancestor.

I prefer Reeking Boxes since I'm past that point where you have so much money you don't know what to do with it. Besides, Reeking Boxes are always profitable, especially on harder locations.

Why do you ask?