I think it would be an impossible job for mods to decide what's a sensible revival of a topic and what's...less sensible.

It's good to see people use the search to find information...instead of asking a question already asked and answered a dozen times before.
And when they have something to say about it...well...sure they can reply. Drawback...it's possible the original posting became heavily outdated...for instance the original poster (and those who replied) might have a different opinion now or triple the amount of kilts etc.

The welcome posts...I don't see the problem. It's visible you replied to a post, so when it returns...don't bother checking it again.
Not a big deal, even though it makes little sense.