i doubt itd be hard to do because people translate japanese manga and doujinshi without the clean images pretty well

Removing text from the speech bubbles is actually really easy since they are just plain white and letters easily erasable.

when it comes to half-opacity screentoned word balloons and sound effects against detailed backgrounds, the difficulty spikes in terms of cleanup

Yeah, but I saw the comic and saw the speech bubbles are plain white.

it's not just the speech bubbles, he's also including the sound effects and basically any other text that isn't on a flat-color surface

Those are never modified in manga, either. Translators write notes next to them.

depends on the company, some leave it alone, others actually put in the effort to edit them out and add in the english translation, the one I worked with did the latter

Idk how to understand weeabuu nor moonspeak

It wouldn't be too difficult, just time consuming~ Having to edit out most of the text in some cases could be saved time by just overlaying over it.

Just would take some persistence. ^_^

it's possible, I've had experience doing some cleanup of manga pages to insert in english translations

it can be a mix of easy to a pain in the ass, depending on how much detailing and redrawing may be needed.

There are groups that do the opposite professionally Japanese to English properly cleaned so getting them to do it the other way around shouldn't be to hard but of course you would most likely have to pay. The only easy place I know to get in touch with a lot of such groups is the e-hentai.org forums in the bounty section. You can make a request instead for free but you may end up waiting forever since it's a very non standard request.

From what I've seen, it will have varying levels of difficulty. The words in the speech bubbles will be easy to do. The thought texts and sound effects will be more difficult to edit, as you'd have to erase, then draw over the erasure. It's still possible to do this without an original file, just more tedious.

As for the translation itself, it's easiest if you're English/Japanese bilingual, or at the very least have had a few years of experience of learning both plus a dictionary on hand, but I would hazard a guess that you're pretty experienced with Japanese as well as English. I personally have a good grasp on the grammar, it's the thousands of kanji that trip me up constantly XD

despite having borrowed most of its writing system to Chinese, Japanese has unique grammar. You can't translate sentences without messing them up or changing them completely.
Also, speech is usually written vertically, but it doesn't have to be the case.
And reading order is from right to left.

Japanese language isn't that complicated, but learning it is very confusing because you have to change all of your language or expression habits you get from your own language.
If you want an example, the only way to say "There's a pan on the desk" is "on the top of te desk a pen exists".

I only took one year of Japanese, but I'm fluent in Chinese... my Japanese is kindergarten level

ok it is hard ^^ also i dont know if its really worth ^^;;

For the text in the bubbles its very easy. But for the non-bubble text, it will be a bit harder. Not impossible though