DA:O Connor or Isolde?

I've got a problem. I'm on my first playthrough as a good character. I'm at Redcliffe and I'm trying to save Connor without having to kill anyone.
Also, if I have to, is it a bad idea to use Isolde as a sacrifice for the blood ritual? I heard if you kill Connor, it causes some problems with Leliana and Alistair, which would also be bad for this playthrough lol... please tell me I didn't somehow screw myself. I did the Redcliffe first, got bored, did half of the main quest and completed side quest and decided to go to the mage tower to get Wynne.
I think I sided with the templars, but I told Cullen that I didn't want innocent blood on my hand. After Uldred's fight, Cullen came running in after the fight and a cut scene whisped me away to the entrance, now Irving wasn't there, and I was too lazy to run all the way back up and see if he was there. Yes I used Litany of Adralla during combat. I just assumed Irving was dead...>.> I didn't know he could die . Also there this Mage dude on my party camp and there a supply box that let you turn in runes.

There's gonna by spoilers below.

If Cullens showed up at the end of Broken Circle it means all the mages are dead, so your playthrough defaulted to "sided with the Templars". Also, you can only save Connor's life if Jowan is still around.

I personally suggest that you kill Connor and let Isolde do it (everyone approve of this choice except Oghren).