Milky oil and loss of coolant

More likely an intake manifold gasket is leaking. Blown intake gaskets are pretty common on these engines. I have seen a few of them myself. So is the torque converter control (TCC) solenoid.

As for testing for a blown head gasket vs an intake manifold gasket leak, check the following guide: https://www.2carpros.com/articles/head-gasket-blown-test.

As for the revving, hopefully it is not a bad transmission. I would suggest checking the transmission fluid before driving anywhere. If it is low, then add some and take it for a ride.

Yes, both common issues.

The intake gaskets are very common. When GM redesigned the engines to make them faster to assemble on the line they really messed up. If you look at the earlier generation of both the 4.3 and 5.7 you will see that the heads are cut at an angle and the intake manifold bolts are ninety degrees to that angle. That allows for the intake gasket to be compressed evenly across its entire face. When they changed that they kept the same angle cut on the intakes but now the intake bolts actually are at ninety degrees to the top of the cylinder block. Not the heads. When the gaskets are set in place and torqued they are compressed in a wedge shape with the bottom being crushed thin and the top barely tight. They also changed the gaskets to a plastic composite. Those two changes result in the gaskets failing.
Many folks like to say it is from the Dex Cool. The problem with that is that GM used Dex in every vehicle, the 4.3/5.7 are the ones that were re-designed and have the gasket failures and every one I have ever changed the gasket itself was broken mechanically, not chemically damaged.