I'd have a bit of a quandry myself on this one....
For the first finder I would say delete the log (with an accompanying email stating that that's what you are doing) as they did not read the instructions properly.
For the second finder I have a bit more sympathy as they got fooled by the first finder's extra log book, but you can't delete one with out deleting the other (neither one found the real cache). So delete the second one as well.
On the second topic, moving the the cache a few feet away does not constitute a new cache, and should not be counted as a new "find" by a cacher. And most cachers are aware of this;usually it's the newer cachers who don't realize this yet. Either way I wouldn't worry about it, just leave the entries as they are and as you say, "don't sweat it". I have a few logs like that on some of my hides as well, and I just leave them be. At the end of the day it doesn't really matter...I still have to feed the cat whether somebody has an extra find or not!