Hi,
Please be patient, you posted on a Friday before a holiday weekend and you asked a lot of questions most of which is covered in documentation.
Also this is the bug forum not the forum for general questions. Please in the future only post bug reports in this forum.
1. Possibly an error is happening, see basic troubleshooting to learn how to check the log for errors, also see supporting large file uploads.
2. No there is no current feature for that, you can schedule publishing of an instance of shared files but not at the file level currently.
3. Nothing will happen to the files if you move an instance from one page to another or remove it from a page, but if you delete the instance completely I think it "should" delete the files in theory but to be honest I think it is not implemented yet and will just leave the files on disk. If your intention is to delete the files then it is best to delete them from the module instance before deleting the module instance.
4. See Using the Chat Feature, you need a Windows Live App Id
5. More than 2 people can chat with you at a time but not with each other, it is not like a chat room. Basically you use your desktop Live Messenger and any number of web visitors can send messages to you and you can reply from your desktop messenger client. It is more of a support kind of chat than a social site feature
6. Labels and button strings come from resource files, the Swedish resource files are not up to date if you would like to help update them that would be great. If there are missing keys it will fall back to English. See Localization for more information how it works and how to contribute with translation.
7. Same as 6
8. Yes you need the same url structure on development as production, see Moving an installation of mojoPortal from one server to another.
9. Yes, though typically you need to create your own table for custom stuff you can use the same db and we do have a built in ModuleSettings which allows storing key value pairs in an existing table. See Developer Docs and Hello World. There is a whole series of videos that are well worth watching if you want to develop custom features. A little time invested watching those will save you time later and answer many questions.
Hope it helps,
Joe