No, There's no fee on this forum for publishing it on a thread unless you want to advertise on this forum like installing banners, you need to contact administrator first for that. All it take is to pay someone who have done your works or you can deal with them just for thanks. Negotiation are welcomes.

Yes, you can publish it on yourself but there's no need anymore to do that after someone already publish it otherwise if you will publish it with different language.

You need to have an active slack and/or telegram channel where you can answer user's queries and also many successful ICOs have their own bounty campaigns like bounty pool/translation/social media/newsletter/signature campaigns that help the project to get publicty on the forum as well as on social media platforms/local platforms.