The Colony is most likely not a factor in the raiding of LaLa Land. They are too far south, and they were staying close originally because that was an evac site for two or three days I believe. And during those two or three days they were under constant attack. So that burns their time raiding LA by being trapped by zombies hoping for a way out.
The Mallers may have taken care of a good many number of the areas near them and LAX. However, I don't think that every single solitary store that got raided in LA was at the hand of the Mallers. If nothing else, there has got to be way too many stores for the Mallers to take care of by themselves. 200 people or not, you aren't sending out all 200 mallers on scavenging missions at once, especially not if they have taken slaves that they have to keep track of.
If you fan it out from
the mall, and take into account breaking them out would have taken at least half a day what's being said is the mallers made it around 25 miles and scavenged every single store in between the Mall and
Locked and Loaded. That doesn't seem all that plausible to me. It's just way too much ground to cover. Even if you narrow the window to stores between
the Tower and Locked and Loaded (the route that
Angel and
Saul took to find
Burt) that's still a lot of ground to cover (traveling from the Mall to the Tower area, and
then starting to scavenge seems....not right to me at all)
My guess, because I can't think of it happening in any other way, is
Scratch is the one who jacked Burt's wall safe full of stuff before she got to
Eastern Bay to break everyone out. All the damage had been done before Burt got there, so Scratch must live on the East side of the city to get to Locked and Loaded before Burt could, steal a bunch of stuff, and leave Burt to be trapped in the bathroom. As for the rest of the stores? Well, we've met/know of at least 4 sizable groups of survivors. How many more groups were out there that we don't know about?