99 Crown Vic Odd overheat issues

Do you know if you have good circulation in cooling system? Is water pump showing any signs of weakening? The impeller blades can corrode away, I've pulled more than a few that were little more than nubs. Check it isn't something silly like a slipping serpentine belt (could also explain lack of AC). As to the oil smell, may want to check oil pressure with a manual gauge. If you're getting an 'oil smell' it's leaking somewhere, if it smells like burning oil look around valve covers and heads, and getting on headers. (valve and piston blowby might be another concern.) may want to run some tests as problem may be internal to engine - a good leak down test and cylinder compression to start with.

The Thermostat was replaced already, so I can't say that's the problem. Already tried checking fluid flow, it's movin' and not boiling over.

You didn't say if you replaced the radiator , or flushed it ?

I did say I replaced the entire cooling system, so...