Good questions, all.
No matter how you do it, you will not be able to see the TFW start pages in TSATC.
*WARNING*: Following procedure is a pain in the ass
You COULD install TFW and TSATC to seperate directories (seperate from eachother AND ATF), apply the patch to each, and then copy the contents of the TFW directory over to the ATF directory, followed by the TSATC directory.
Then, if you wanted to play TFW, copy the "Setup.txt" file from the TFW directory to the ATF directory (containing all three games). If you want to play the TSATC game, copy the "setup.txt" file from the
TSATC directory to the ATF directory.
You can do this any number of times, when you want to switch between the games. Just make sure you
copy the setup.txt file each time, rather than
move it, which will eventually end up with you losing one or the other setup.txt file and having to reinstall both games to get them back.
Of course all of this is unneccessary if you just want to start the scenarios from each game using the "Start imported scenario" button, rather than selecting them from the scenario start pages.
To answer your other question, all ATF Engine games share a single executable
name. The engines for each game are a different version, and the early version cannot run all later version scenarios, which is why the news game should always be the last one copied over to the common folder. But they are all called "atf.exe" so that the shortcuts will all work without modification, allowing you to over-install the games using the procedure I described in my previous post.