UUID=50560-jhks9-string-id-etc / etx4 noatime,discard,defaults 1 2
You don't need the 'defaults' string if there is any other option - it's just a placeholder
noatime is a good idea for any file system.
Nearly every Linux filesystem you might want to consider takes the "discard" option including vfat, btrfs, ext3/4, xfs.
UUID=50560-jhks9-string-id-etc / ext4 noatime,discard 1 2
Yes ,TRIM is automatic with swap and has been for a while.
Recently (~2.6.36 IIRC) LVM supports TRIM passthrough.
FWIW - IF you've been using your disk without the TRIM option, then any blocks deleted from the file system are not known to be free by the drive. So on a clean install all the writes are fine, but when you start upgrading packages ...or otherwise deleting files - the block go into limbo. It's not a big deal for a few percent of the disk size - but it may be a long long time before those blocks ar recouped through garbage collection.