I don't have much help for you for the shoes. Sorry.
As for the scab picking, we had the same thing with my step daughter. It's slightly better now, although she will occasionally do it still. I really think she was just bored, although she'd never admit it. Also, it is a "weird" thing on your body - to them, it is there to pick at. I tried band-aids as others mentioned - she loved them. I tried punishing. She did it again while being punished. I tried rewards. Didn't matter.
What we finally did - and I guess I'd suggest it for the shoes, too - is to just resign yourself to sound like a broken record. No matter how mad you get, no matter how awful she looks, just simply say "don't pick" or "shoes please" or whatever. Nothing more, nothing less. You'll say it a bazillion times and be really irritated, but she's bound to stop sooner or later. Either she'll get tired of hearing it all the time or she'll realize it's not a huge issue anymore and it won't get the attention she wants about it.
I guarantee you she won't get married with scabs all over her body. And in the meantime, she's six. Most people (well, anyone who has been around kids for any length of time) will recognize that kids are constantly dirty and bruised/scraped up and won't judge you on it.
Good luck and relax!