Lets back your theory up with some suspicious moments:
1. CH927 P1
"Italian Aska" was the name of the restaurant.
Asuka was the name of the victim.
Some kind of foreboding to Asaka?
2. CH887 P16
Higo´s favourite song is Yokos "Dandelion". This can be understood also as "Dandy Lion" according to Conan.
"Dandy Lion" is better known as "Cowardly Lion" from the wizard of Oz.
Dandy Lion is described as loyal but ...
"... he lacked the nerve of a lion and was instead a mouse. "I'm afraid there's no denyin' "
Losing nerves?
... and maybe messing up sth? Like the Haneda-case?
" Pirates spirit is such a weak horse " = " Rum is so weak / has weak nerves" ?
Might kinda fit.
3. CH885 P7
Higo is part of Big Osaka.
They took the
second place in the
inter-high.
Big
Osaka = BO = Black Org - allusion?
Possible.
It´s kinda weird that Conan mentions that Higo went to a school in the Kantou-region and dont "solve this comment" as if
it´s up to the reader to understand the meaning of it. But im not sure about this.
4.
There are even some receipes which use Rum to caramellize onions.
Rest is self-explaining.