Oil on closed intake valves

If it were me I'd do a leakdown (which can be done cold and without the intake). Even cold the leakage should be higher but even for all holes. It looks to me like if the heads were not gone through out of the box there might be seat and/guide issues, or there may be ring seal issues, or head gaskets, or all of the above. Coolant will be blown all through the intake so it's not a big surprise if one had a leak the others might show something. I can tell you - that ain't right or normal. So i'd do the diagnostics that you can, but expect to pull those heads.