That's a good question, about the 2018 expenses.  First, many "retainers" are deposited to an attorney trust account and not considered paid for fees until billed.  All or part might be refundable.  Second, the deduction is limited to recovery, and would Congress have intended to allow a deduction only for payments after the case is won?  I would see it as more like a start-up expense, or purchase of a depreciable asset not placed in service until a subsequent year.  You could try calling IRS three times and pick the best of three different answers.