Hi there! Eightysix sure is a cutie! Angle and non-clarity of the picture makes it hard to give contstructive criticism.
Shelby definitely has a pretty big angle on the front pasterns - I'd be concerned about how that will affect her in her later years or if she is worked hard.
Patty definitely is underweight. Reason I say this is because her ribs are clearly visible, even in a poor photograph, which indicates to me that they'd be more visible in a better photograph. Also (others feel free to correct me), the ribs that are visible have a "frail" look to them, not like they are ribs that are just showing up under a healthy layer of fat. The bottom picture she looks a little sucked up at the flank, too. She is still, for all intents and purposes, a younger horse, so I'd be concerned about an underlying health issue. When was the last time her teeth were done? Have you looked at her manure to see if there are whole grains in it (whole grains indicate that she is having troubles chewing her food properly, which in turn suggests the need for floating)? Our vet's constant suggestion for horses who come to our barn underweight is to start by adding more hay, as much as they will eat.
Also, what is the reason for worming monthly (8 wk intervals is generally sufficient, although perhaps this is different in different climates?)? If you suspect that she has worms that the "normal" maintenance dose isn't correcting, talk to your vet about double dosing or getting a prescription dose for her. KEEP IN MIND - most over the counter wormers do NOT treat tapeworm. You need to dose with Zimectrin Gold, Equimax or Quest Plus gel to treat tapeworm - those are the only three I know of that are readily available that treat tapeworm.
She's not deathly thin or anything - just could use a few more groceries
Overall, your horses are pretty!