None of the above, as they're all very risky. Basically you're assuming that you can cancel an award and that it will go back into the reward fare bucket in order to get it again (as a UUA or otherwise), but this isnt always the case. You could cancel the award and it just goes; then you're left with revenue ticket.

Similarly, getting an outbound award whilst its available may seem like a good idea, but then awards for the return may never turn up. Then you're left with paying a full fare one-way ticket which is very expensive, or having to cancel your outbound awards and buying a normal revenue return ticket (which may not be at optimal prices either).

You made the assumption that prices will come down as you get nearer to departurer, but quite the opposite is true (notwithstanding sales which come and go).

I'd say that a decent option is to buy WT+ return tickets now, and UUA the outbound which is available. Then you're ready to UUA the return if it becomes available, which may only be a few days prior to departure. If nothing comes available, you're still in WT+ which isnt the end of the world, and you've saved a pretty penny.