Second Generation Gore-tex includes Goretex Classic, XCR, Paclite, Windstopper, and the new ProShell (these all include a thin PU membrane).
At least for Windstopper, Im not sure this is the case. Put a windstopper laminate under a bubbler tester, and you will see that air bubbles right through it, at a comparable level as eVENT. And even Gore admits on its own Windstoppr site that it passes some air.
I ProShell is identical to XCR except for the tricot protective 3rd layer. Instead of using tricot, ProShell uses a durable protein layer that protects the vulnerable Gore-tex membrane from abrasion but allows it to be lighter and more packable. Packlite, again identical to XCR, does this as well, but isn't as durable as ProShell.
I don't think Pro Shell uses a protein. Instead of a tricot knit lining, generaly made from 40 denier yarns, it uses a woven liner made from 15 denier yarns. It makes the lining lighter and more durable. Paclite does away with a lining by adding carbon to the PU-layer. Nice in theory bu it's very condensation prone. The membrane in itself appears to be same although the PU-layer appears to be thinner from the appearance from XCR. Possibly, and surprisingly, there's a good possibilty that the pores from the Gore membranes are also covered with a hydrophobic and oleophobic coating just like eVENT. Why they would use both this coating and the PU-layer is unclear to me.
The thing to remember is that XCR, Paclite, Windstopper, and ProShell all have the same breathability.
Not exactly. As explained windstopper is slightly air permeable and should perform like eVENT. But what can make a big difference is the combination of the membrane with face fabrics and scrims. These have an influence on breathability too.
eVent, on the other hand, works best at low-humidity levels (when you need it most) because it allows the early water vapor to escape, not allowing the jacket to get to the high-humidity levels that Gore works 'well' in.
More exactly, since eVENT functions independently of the humidity gradient, it works equally well at low and high humidity levels.