BocoDragon
or, How I Learned to Stop Worrying and Realize This Assgrab is Delicious
That's true. It does invoke that imagery, but it just felt like a lot of it was due to Nomura's themes of making Lucis all black to go against Niflheim's white attire.
Not that it makes any difference, though.
I'd say it's quite intentional. Lucis is basically modern day Japan, to a degree that no other kingdom has ever been in an FF game.
I think they were quite conscious in making the royal family look like a powerful modern business family which... in Japan's case, would be yakuza.