For bleedi,g the air out of these swaps, it is ESSENTIAL to fill it completely, burp it at the bleeder at the tstat housing, then clamp that 1/2" hose off that goes to the top of the radiator, and remove the hose from the radiator. It is the only way to get that air bubble purged out, and gets most of the air out quickly. Then bring it up to temp, drive it to push the air out to the radiator, let it cool off, and repeat the process of purgi,g the air out of the radiator by clamping the small hose and removing it until you get straight coolant coming out of the top of the radiator. It's a pain, but it's the only effective way I've found tp get the air out of one of these. Your other issue is the 6.5's bottle probably has the coolant level too low so it's not the highest point. The duramax bottle has the coolant level come right up to the top, but iirc the 6.5l bottle did not.
As to the haze, get some GM upper engine/injector cleaner, and do the injector flush on them. They may be gummed up from sitting so long, and a good cleaning with break the hard varnish deposits loose and let the nozzles seal better again.
Edit: just looked at your pics under the hood, and that coolant bottle setup will never work right. It will suck air back into the system as the degas bottle MUST be the highest point. You need to get that bottle moved up as high as possible, otherwise you WILL have problems later on. The bottle's coolant level needs to be as high or higher than that 3/8" hose that comes off the turbo over to the coolant pipe.