nanowrimo_lj | Accents!

In my NaNo, I'm trying to emphasize the different nationalities of the characters. They all belong to a secret society that draws most of its membership from Europe, so they come from many different countries, but the organization's based in London, so they primarily speak English. A lot of them, though, especially the newer members, still have accents.

I want to phonetically spell out their accents, partly to cue their nationalities and partly to emphasize their different levels of fluency with English. My German character joined recently and still has a heavy accent, whereas my French character has been in the group longer and speaks more fluently, but neither of them are quite as familiar with English as my character from America, who doesn't really have a phonetic accent, but who speaks very casually.

For comparison, this is an excerpt with how I'm considering writing the German character's dialogue (if this isn't allowed, please let me know!):

“It has potensial. If ve can get zose Templar to fall back srough here und head srough here, ve can place charges at ze lip of ze valley, above zat exit und at ze entranse…zen remote detonade ze charges, und force ze Camorra to come zis vay — giving us ze high ground und bunching zem up. Perhaps setting some marksmen und mortahrs along de lip of ze valley will mek it easier.”

This is how I'm considering writing the French character's dialogue:

"Marissa ‘as been leaving quotes about cats with obscenely bad grammar and spelling on ze whiteboard again. In between painting ze seats with glue and waxing ze floors. I ‘ope we get deployed soon, or she will blow ze windows out. Again.”

And finally, the American character's dialogue:

“You have one thing to be grateful for, at least. There’s only one of her. Think of how bad it’d be if she had a kid brother or something for backup. ...You okay in there? Thought I heard a thud.”

When I searched how to write accents phonetically, though, I came across a ton of posts insisting that it was better not to do it. In this case, I want to use the phonetic spellings to emphasize the different nationalities/familiarity with English, so does that make it more acceptable for me to do it? And if anyone could tell me if I made some horrible mistake with the accents -- since I'm Chinese, not German or French -- I would be very grateful.

Thank you!

Edited to add:

Now I'm embarrassed XD I honestly wasn't aware of how bad the German was, and I apologize for getting it so wrong. This morning, though, I had a little inkling of an idea. There are quite a few combat scenes planned in the novel. I'm considering not adding phonetic spellings outside of combat, and focusing more on syntactical differences. But during the combat scenes, where most of the dialogue is fairly short and clipped anyhow, I might add in some phonetic spellings, since they'd have more than enunciation to focus on and I can imagine that their accents might get thicker. I'll definitely still tone back the German accent, and probably just have the French character drop 'h's, if I do that.

Thanks for all your responses :)