Wow OK, thanks to the help of long time PA! Nickling, Sylvie Wolf, I was able to clean up the Lost Pokémon page, make it a bit more organized and efficient, and a bunch of other stuff. I still have more basic information to add to the list... like names and types, etc... but that should be a breeze now, now that I got all the heavy lifting out of the way.
For an idea of what it'll look like, take a look at this example entry for the proto-Pokémon, "Twinz".
BTW, where did this info come from? The GS leaks which all the Anons over at /vp/ have been pouring through have uncovered some interesting bits... which include Pokédex entries for these lost proto-Pokémon! Of course the ones that were cut early on don't have any, but some which survived up until the late stages before being cut did get to the point of having their Pokédex entry written up.
In the case of Twinz here, this is about as authentic as it gets! One other fun fact is that, when it was cut, it was replaced by Wobbuffet.... which seems to share some kind of similarity with Twinz here, but I can't put my finger on it....!
Anyways, there is plenty more where this came from, so just keep an eye on the Lost Pokémon page for the next update! Huzzah!