Very late, but actually in the raw that box is empty too. It's a kind of transition panel artists use sometimes to show that time has passed though I think Igedoaha could have executed it a tiny bit better.
Exactly, where would the fun be in that? The boyfriends are supposed to be lame. My generic advice to anyone who can't handle NTR is stop identifying with the boyfriends.
The fact that there's another chapter that requires a sex scene means that there's a very likely chance he's still alive. Unless they got him and yuri it up randomly.
"missing the very long hair tag"
Her hair is a pretty average "long" length; if you look on page 15 you see it only goes to the middle of her back. The girl in the Netori chapter has Very Long Hair.
To be honest I kind of prefer my hentai that way. As Kosuke Haruhito said in his One Point Advice Corner, if a hentai manga doesn't turn you on, then it's failed its job. I'll read h-manga solely for good plots or endearing characters, but they better go hard or go home. Because at that point I'm reading a normal manga with some sex in it. And there's always the exception for art styles I love seeing.