It sounds like she is genetically skittish and nervy, if you've seen this from day one. Probably the main reason she was rejected from detection dog work. I'd try to build her confidence through working with you. Obedience, tug, fetch, you could test her in schutzhund or ring if you have the time and interest a local club. Take her on sniff and go walks, practice bonding games. Find something that really excites her, and work with that. Frisbee, tug... ball... keep it fun. She'll gain confidence.
As for pooping on the patio- take her on multiple walks a day to avoid the mess. Or teach her to eliminate in one part of your yard on command. I've heard of malinois that paint their kennels with poop- but I've never seen it. I think you run into this type of problem if the dog wasn't kept clean as a pup or kenneled too much as a young dog. Not super uncommon but not something I'd want to deal with.