Ok,
Sounds like you've check it ALL out. Try replacing the IACV with another, used they are about $30-40 and new is about $150 from my Honda dealer. Try adjusting the throttle cable again, I've done this a few times and it worked for my GSR swap. That should do it, just loosen it up some more see what that does.

If that neither of those work unplug the connector ont he IACV THEN and only THEN you adjust the idle screw ont he throttle body. Shut off the motor and un plug the ecu fuse under the hood for 1 min and plug the IACV back in. Check the idle if its 750+- 50 rpm's its good to go, if not I don't know what else?