I am looking for the manga where my avatar originates from.
I want to reread it, I remember it being awesome.

IT was removed due to some I guess misunderstandings? from the authors. It was translated and the translation team accidentally? used the wrong author name and the author wrote about potential identity theft on twitter and as such it was taken down.
(why do I remember those details and not the mangas / authors name. silly brain)

I remember that kerfuffle, it was this author:
https://dynasty-scans.com/authors/kamaboko_tarou
There's a booth link to the work your avatar is from.

It's had a bit of popularity with BL communities in Japan (tho much less than in America), so I assume it comes from there.

Ahh, that makes a lot of sense.

ABO

I'd honestly love to know precisely how knowledge of this made its way to her (and Takemiya).

Okay, I see what you're saying. I misunderstood about the circles. So they used 〇 like is done for blanking out letters and such. I haven't seen the raws, I didn't realize the numbers here were re-typeset. Though now that I think about it, of course they were, since they match the lettering.

It looks like that's the interpretation the translator went with, yeah. I think they're zeroes.

You didn't imagine it after all:
https://dynasty-scans.com/chapters/to_die_in_june_ch01#13
(It's right-to-left because of the time period)

Oh, are they? Hanami Ryou has 1X0X, with the zero being just a circle with a dash through it, so I assumed that's how they'd be writing zeroes, not as Xs.

I meant the Xs were originally circles in the raw, so interpreting them as redaction is legitimate but probably not correct in this case (the zero with a dash is from the font used for the translation). Honami's number should actually be 1010 (一◯十◯ or 一◯一◯ depending on the page) so I'm not sure why it's written 1X0X, typo maybe.

I feel like a saw a page with a ブキ showing on a cut-off sign in the background, but now I can't seem to find it.... That makes sense though.

If so, I missed it! I just went off the "with a cold name" (寒そうな*雪*の名前のふね) and the look of the ship.

I've read the whole thing so I can't really join in the overall speculation fairly.

On a side note, I don't think 1XX7 is a date
Maybe those are ID numbers or something like that?

You're right (it's probably 1007 rather than 1XX7 but those ○ are tricky). I'm not sure exactly what the numbers would be called, but each girl has one that's consistently included as part of her designation. 7th Escort Fleet 1007: Tanabe Aka, 7th Escort Fleet 1006: Satsukibara Nae, etc. There's a full list of them, but it contains spoilers.

a large warship

Pretty sure it's Fubuki, and the "boat with a name like a guardian statue" is Kongou. iirc the ships were chosen based on... which ones the author has put together plastic models of.

Is there anyone here that's already looked into this and could confirm whether it was ever actually completed, and how many chapters is runs? From what I understand, the series consists of:

BASH! - 2009-02-15
BASH! ～ある日の生徒会～ ヒゲとメガネと坊主と携帯 - 2009-04-26
BASH!#02 - 2009-08-16
BASH!chain - 2009-11-08
BASH! Noisemaker - 2010-05-04
BASH!after-N - 2010-08-15
BASH! In crimson - 2010-11-14
BASH!スモーキン・ハニー - 2010-12-31

I don't know if you are still looking for this information as the post was made years ago, but just in case:

"BASH! ～ある日の生徒会～ ヒゲとメガネと坊主と携帯" is actually collected in BASH!#02, so I wouldn't count it as a separate issue. There is an issue between the first and second, but it is "BASH! #1.5" (2009-05-05).

There are also two additional issues, from 2012:
BASH![wrong] - 2012-05-05
BASH!Black&Silver - 2012-12-31

So nine unique issues that I know of -- some of them are composed of multiple chapters, but I'm assuming you're more concerned with the book count than chapter count.

Black&Silver contained no indication that it would be the last issue, so I wouldn't say the series is completed so much as on hiatus. I don't follow social media very closely though, so if anything was said about it there it's quite possible I did not see it.