First, the carbs:
You replaced all of those things in the pic except the o-rings?
The larger of the o-rings goes on the bowl drain screw.
The smaller of the o-rings goes on the air/fuel mixture screw. You also have to have the spring and washer on there in the correct order. First you put the spring on, then the washer, then the o-ring.
As for the oil from the exhaust:
There should be abolutely no oil in your exhaust. If there is you have a problem. Was the oil coming out where the exhaust attaches to the cylinder head? Are you sure it wasn't coming out from between the cylinder head and cylinders near the exhaust?