I may be misunderstanding part of your description of the problem... What do you mean the oil looks "chalky". Chalk, soft white stone, used on black boards a couple decades ago?
Oil leaking near the timing belt is not going to affect your coolant in any way. There are a few places where that oil could be coming from: Cam seals, oil pump seal, front main seal, or if the head gasket job wasn't done by the book the lower rear timing case/block union FIPG wasn't applied.
A head gasket doesn't have to leak anything into the cylinder to allow oil and coolant to leak into one another's circuit. The only other ways for the two to mix as you're describing are a seriously cracked head or a seriously cracked block. Just because there's a MHG and ARP fasteners it doesn't mean the job was done right...
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