The version of MPW on Apple's website requires System 7.5.5, which would chew up the RAM on an SE. Though it does run on a 68k. There are older versions that will run in System 6, but I haven't seen those versions in circulation. (Though I do have a copy for System 7.)

Technically, Think Pascal was never freely available. Somebody just discovered that the updater on Symantec's FTP site was essentially the whole deal. Unfortunately it was also pulled a while back.