As a translator, I'm able to upload my translation files, so that contributing with limited internet access is possible.

Yes, this is a kind of backup.

As a translator, I'm able to interact with comments made inside the translation platform with an email client, so that contributing with limited internet access is possible.

That means like a github or pagure issue, when you get a notification, you can answer directly with email.

Optional. We can use existing mailing lists.

As a translator, I'm able to interact with a mailing-list from the translation platform so that interaction issues with limited internet access contributors are limited.

I don’t quite understand your meaning here, but the existing mailing list is a good tool for discussion, communication and interaction.

When you speaks "less dependent on those internet giants' codes or services", do you have privacy requirements in mind?

I think should allow anonymous contributions, 2019 is the International Year for Indigenous Languages https://iyil2019.org, and contributing with a real name to some may fear some people. Does it makes sense?

No privacy concerns.

And I don’t think the anonymous translation is an idea for fedora project. It increases the happenings of irresponsibility translations(for example: low quality, even wrong translation) and makes the translations very hard to maintain.

It’s a not a simple work when fixing a l10n bug.

Using that kind of codes or services may result in unfree, which is the reason we made the last migration.

Also, if such kind of things are used, it increases the risk of unstable connection for certain regions(for example, my place).

Zanata will send email notification to me about the new join request,

but the request will not be shown on my dashboard page. If I want to
approve a request, then at first, I have to click the language link,
which is on the left panel, then search and find my language(zh-CN),
then click the language, and click the request tab in the page to find
the member's name, and click accept or deny.

It shouldn't be like this.

This is totally a zanata design problem. Not the procedure problem.

Here are my proposition:

As an internet user, I'm able to register to the Fedora project and directly contribute translation without having to leave the Fedora Localization Platform so that project onboarding is painless and doesn't requires coordinator action.

For the future, translation platform and the fp.o should be well integrated. When a new contributor is approved by L10n team, then he/she will begin their translation on the platform, no further approve is needed.

We didn’t achieve this goal when we were in transifex, and also the current one.

One of the platform maintainers or developers should be a translator
himself/herself, or he/she has done some L10n work. Only a real
translator knows what kind of the interface, what features are needed,
and where and how these things are placed, arranged among the web pages.
True, we certainly need people who understand the diversity of languages to manage our tools and community. And governance needs to be open and community's opinion should be solicited.