Overlooked is maybe the wrong word but he was not starting, Origi was. Remember we are talking about the time when Chelsea opted to let him go, not what he has done subsequently. You are right though, there aren't many of his type around these days though Chelsea themselves have a better one...
I meant at the time. They clearly didn't think he'd make it anytime soon and they were operating in a different market to Everton. Remember he was also being overlooked for Belgium so they weren't alone in having their doubts.
All the more reason to do so on this occasion. They got those two for (relative) peanuts and I am sure they were as surprised as anyone when De Bruyne went for £55m! I think they did ok getting £28m for Lukaku though in truth.
If they let him go for as little as £5m you can be sure they will insist on a buyback.
My guess would be around £8m. And were it not for the disappointing spell in the Prem with Palace it'd be a load more.