Hi Mags,
I'm not sure linking to help pages from more places will help. Most people don't read help pages.
Contextual instructions are more likely to be read. Or, even better, changing the flow of the process to fit the needs.
This is why when you complete a merge you're now redirected to the edit page and why it's impossible to merge a lower-numbered ID into a higher-numbered ID with the same LNAB. So, I'm not why that needs to be explained at all. It only comes in play when someone is merging three or more duplicates for the same person. Is that what you mean?
Regarding including an explanation for merge proposals, we could make that mandatory, like we do with rejecting merge proposals or postponing them.
Chris