All of those songs from KH1 have loop flags in the bgm, I even went ahead and listened to them in winamp and foobar using highly experimental (making sure to enable the setting "force all songs to play indefinitely"). Almost all of the PSFs for KH1/2 set the song length + fade time to be similar to the track lengths of the OST, but even then I'm fairly certain that all songs at least hit the loop end before fading. If there were no tags set for length + fade it would be set to the default length + fade of your psf player (which is usually set to 2:50 + 10 seconds of fade, so a track length of 3:00) Now, if you want these songs to play infinitely make sure you check the option "force all songs to play indefinitely" in your psf player.
vgmtrans can decompress and read the .bgm and .wd in the psf2's. Loop begin and loop end are typically in the first music track (I believe it's colored yellow? If you click on the yellow portion and look in the bottom left/right it should say something like "loop start" or "loop end"). vgmtrans documents the .wd/.bgm formats fairly well. A few things it does not document is reverb type @0x09 of the bgm header and master volume/reverb depth(?) @0x0A - 0x13, individual track lengths (they're 4 bytes directly before each bgm, iirc it reads this properly). I believe vag/vas is played via "0x14 0x##" (0x## being the current note's stream id), I've only seen it w/ Lazy Afternoons. Also, instrument offsets start @0x20 in the WD.