are you on PC or console? If on PC simply use console commands to move esbern and delphine to where you're standing, check the wiki for the commands.
Its's on xbox so I don't have the console commands available.
It seems to be a trend; you find a quest item or quest location prematurely, and everything gets messed up.
It would be sweet if the system was smarter than this.
Yeah, I got the impression when searching the internet for solutions that there are a lot of problems with skyrim, not only this mission. I'm waiting for the 1.4 patch to be available, but this quest wasn't listed in the things that the patch fixes, and you never know if or when Bethesda includes a fix for this problem in a patch.
So now I'm trying to figure out if I should go back before I found the cave and restart from there or if I should go ahead and play side quests and that stuff and hope/pray that a patch will be coming and fix this problem for me.
Is there anyone that thinks that this will be included in a patch?