After solving this (and getting an answer distinct from the ones everyone else who commented found), I wrote a quick and dirty python script and ran it on the ENABLE wordlist. There are in fact 1290 different correct answers. Here's 10 random ones (in base64):
Y2FsdW1ueQpkZW50aXN0CnJ1c3RpbmcKY29ua2VycwpkZW5zZWx5CnVyY2hpbnMKbm9uc2tlZAp2ZW5kb3JzCmNoaW5rcwpudWRpc3RzCg==
I took your wordlist and compared it against mine; there are a lot of (mostly really obscure) words that site knows that aren't on the version of the ENABLE list I have (which might be out of date?). The three words you had that I didn't which I actually recognized as words are a25vd2hvdywgbW9ub255bSwgYW5kIG5vb25lcgo=
The others are much, much more obscure --- a randomly selected one is ZW5vc2VzCg==.
Anyways, awesome regex. My technique was a lot less compact, writing fairly unimaginative, workmanlike python code to test out each of the individual criteria.
