I would surely take a cutting and go to the nursery. I have a nursery and it's our job to help, advise and make right anything that comes off our lot - hopefully they will advise and fix. As far as the cedar rust - if there are cedars within 5 miles, they may be the culprits. If it's bad, pluck the effected leaves and bag them, don't
compost or burn. You can polish the rust off the apple skin.