1. In general, I would say someone other than the BA, although I do know quite a few technical BAs who can and do produce technical specs.
2. Depends on the organization, but most often in my experience, the BA writes the BRD. Ideally, it should happen as early as possible. In fact, it's usually the first thing I start on. Level of detail depends on the organization, the size and impact of the project, and the needs of the stakeholders. Sometimes it's no more than a bulleted list. Sometimes it's a fully dressed document. Timing of signoffs is also relative, but generally for me, I want high-level stakeholder agreement on the BRD before I start meeting with subject matter experts. I have never included mockups in a BRD, and can't think of a reason why I ever would.
3. At the risk of repeating myself, depends on the organization, the size and impact of the project, and the needs of the stakeholders. 
Google will likely get you lots and lots of sample templates to peruse.
4. I believe this was answered quite well in your other thread.
5. The list of possibilities in long. I suggest you take a look at IIBA's Business Analysis Body of Knowledge and pull from it what seems relevant to your organization, project, and team.
6. See above #5 answer.
7. I responded to this one in your other thread.
8. Honestly, a good BA could do the job with a pick and a stone tablet. Or, a whiteboard and some dry erase markers. haha
9. and 10. You got a good response to these in your other threads.