I have given this question a bit more thougt and have come up with a plan. Have a look here and see what you think. Feel free to add comments or suggestions.
I have modified my suggestion a bit. It is still messy, but there is probably no helping that.
I'm still trying to take it all in - no matter how we tackle it, the whole situation is messy. I think you are on the right lines, but an obvious problem is that we have to remember to come back to something 6 months or a year later. There's no way of setting up a reminder, so individuals would have to use their own diaries - not the best solution.
We probably need to think a bit longer, but I have no suggestions, atm.
I agree. At the very least we should have a solution to the DPL problems that we can trust, before we proceed.
An idea for keeping track of name changes just occured to me - the template setting up the announcement at the top of the page could also add the page to a special (hidden?) category, fx "ChangeName". It won't actually notify us, but at least we would have an easy way to localize the pages, that needs taking care of.