There is no Fifth Amendment right with WT judicial committees. If you choose not to answer their questions, it can be considered the same as deliberate failure to appear and a flagrant disregard for theocratic order. The appeal committee will then approve the public announcement of the original committee's decision to disfellowship you.
The elders have already informed you that there is no need for witnesses at this second meeting with the appeal committee. They will probably not allow your legal representation into the room. So you will either meet with the elders alone or not meet with them. If you choose not meet with them, that is a deliberate failure to appear. If you choose to meet with them, be prepared for the questions you may not want to answer.
The WT has the judicial committee arrangement designed to their advantage. Unless the elders make a serious error in judgment, the accused will usually lose.