1 That one may be a JMdict artifact; it looks like someone added a whole bunch of current slang in 2007, including the derogatory ikemen, while the positive one wasn't added until 2011. Google, meanwhile, treats them interchangeably, so it's hard to test with an image search (oddly, insisting on a search for é€ã‘面 included a picture of the definitely female, definitely attractive Yui Okada).

Both were updated on 4/16/2012, when there was apparently a major effort to work through some of the slang entries (such as adding ãƒŒãƒ¼ãƒ‰ãƒ« meaning both "noodle" and "TV personality who has appeared in the nude" (nude idol)).

-j

2  ikemen meaning "hunk" appears in Dog Days Dash ep 10 about 13:40. So that one, at least, is a real usage.

3

I knew "ikemen" as "cool guy" before this post, so if it's slang, it's fairly commonly-used slang.  (In anime-land, at least.)

Finding things like this that make you grin is one of the best parts of learning a new language.  "Lock" and "key" both being "kagi" was one of my favorites.