I understand you are in a bad situation and you are limited with what you can/can't do since you are just watching these birds for a friend. It sounds like you have around another 20days before they come back home.
Pick No More or Blue Kote can help hide redness and provide antiseptic/healing to any broken skin/scrapes ect., they will not resolve/prevent the picking and overcrowding.
Sometimes there is no easy fix. Run and coop expansion or reducing the number of birds in that space are the 2 best solutions to this particular situation. Re-homing the Barred Rocks would likely help, they are both in the best shape feather wise, sell them on Craigslist as a pair since re-homing is stressful enough and they will have a buddy. Alternatively, they should make a nice meal, but I'm not a fan of just culling a healthy laying hen that has a few more years of production left in her.
As for the pecking the hands harder during treat time, pecking at your freckles/toes, etc., that is not that unusual, but if it's a problem, then just scatter treats broadly and stop hand feeding. Barred Rocks, ime, are food driven. These 2 are top girls, they will be more pushy than the others, this is part of the pecking order/flock dynamics. Given enough room some of this "unwanted behavior" will go away.
Pinless Peepers you can try those as a short term fix until the owner gets home to make some difficult decisions.