There are a lot of clothes in this game that favour female characters. Gorgeous dresses and lots of skirts.
I've seen more people make the opposite complaint - that there is too much feminine clothing, and not enough for males!
I don't think it's that bad in either direction, but there are definitely some gear pieces that could have had a nice masculine variation, but only have the one feminine design. (eg. the "sky pirate" mage outfits and "ruby cotton" healer dress.)
And while there are few extremely long hairstyles, there are plenty of feminine ones. You're clearly using one. So is my character.
Also I assure you that as a probably-rare example of someone who did set their female character's bust slider to zero (which is still not quite flat-chested), there is a definite and noticable difference between how shirts and dresses look on my character compared to people using a higher setting.
If you want to actually see the difference it makes, you can do that in the character creator. Start a new character, go through the stages to where you pick a job for them, set it to display them in their job gear, then backtrack to the character customisation. Adjust the bust slider and you can directly see the gear change shape in response.
I haven't even noticed that.
It's possible that they are able to have more detailed physics operating in these areas because the game doesn't need to be thinking about other players or enemies or all the other things it has to be displaying in larger, busier zones.
Minfilia has not been killed off. She is clearly 'alive' in her aetherial state, possibly an equivalent opposite to Elidibus, and was sent on a task by Hydaelyn. It seemed fairly clear to me that she was being set up to return at a later part of the story.
I'm also fairly sure we see her fighting as a pugilist during the "rescue from Castrum Centri" quest. But mostly her importance to the Scions was as a diplomat and organiser - not a glamourous fighting role, but a critical one for an organisation!
And it is literally impossible to set up a character with her body shape. At a game level, it's built into her dress - including the Mog Station version that players can equip.