Jemmi, surnames would be preferable I think - that's the way the death notices are listed and that's what prompts my dear old Dad to read the rest of the notice and check if "Smith, Joe" is related to us or just someone who happens to have the same name.
Re the number of surnames, hm...I'd be looking at about 6-8 surnames I think; don't think that's too onerous for a one off set up. I wouldn't expect to input all the first names though.
So I'd be looking to get an email of all the "Smiths, Jones, Greens" etc., who have death notices; they may or may not belong to me, but I can make that judgement when I read it.
The thing is that I would have to be certain that you would have all the major national papers covered?