Hi,
Ad.1 What we do is to have projects and subprojects with the structure somehow similiar to what you have:
- Customer cases
- customer1
- project1A
- subproject11
issues
- subproject12
issues
In CP you can see all issues at the "Customer cases" level but the roles like Reporter or Developer (which is adequate to Customer and Support engineer) can create new issies only at the subproject level.
Customers has rights only to their "CustomerX" project and all subprojects so they do not see issues from other customers.
Ad.2. You can create subprojects, with subprojects and so on. But keeping to much levels makes the structure difficult to navigate.
Ad.3. I do not know if it is possible right now. Tagging is planned feature.
Ad.4. We use it in Polish and English simultanesly.
Ad.5 This works OK.
Ad.6 For this you need plugin. Look for it at github. We will use it in a near future.
Ad.7. You should write what you expect. We rather ask customers to write email to common account eg. issues@exapmple.com, that account is mapped in chiliproject to receive issues to one CP project. there our support people distribute it to the other projects.
You could also write a rule so the email can be put to corresponding CP project based on email addres
Ad.8. Best place is to look at redmine.org or github.
Best regards
Pawel