Just to be clear, you replaced everything in the PCV right? Breather box, all hoses and the flame trap (not sure if your car has a flame trap). Nothing old left to cause a clog?

Couple of other thoughts:
1. The smoke out of the oil tube and cap could be a sludge buildup in the valve lifters. Do you use synthetic oil? Conventional oil usage in the 5 and 6 cylinder engines can cause this. You can try and clean it by running Marvel Mystery oil with your oil for a short time. Or some other safe cleaner. Also doing an Italian tune up might help. Take the car out on the highway and with the engine warmed up run the engine at 4000+ rpms for at least 5 minutes. The sludge buildup can occur if you only drive in town at low engine rpm’s. High revs can burn it off. Long highway trips are your engine’s friend. This happened to my 93 850.

2. Not sure about the leak... Is the pipe you’re referring to perhaps the EGR pipe? It is not uncommon for the EGR pipe or valve to clog on any Volvo engine with age and miles. Is the leak right where the pipe attaches to the engine? Not sure if there is a gasket there. Maybe others will chime in...
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Will I buy another Volvo??? We'll see....