Some of that is right, and some is wrong... at least in my experience. Mine will pick up food intended for my cories, but it doesn't prevent them from eating algae. They'll eat the tablets until they've dissolved, and then they don't seem very interested in burrowing for food like the cories do... they go back to grooming plants.
They seem to establish their own "territory" for a home. My biggest gets in a hole in my driftwood.... my next biggest gets under a section of the driftwood on the back side. The remaining 3 are hard to tell apart... and they seem to hang out in/arount my hornwort, under a rock that was used to hold my driftwood in place and left there after they made it home, or near my wooden airstone.
And mine are in with Alternanther Reickii Red... and they haven't bothered it. If anything, they keep screwing up my dwarf hairgrass by trying to dig through it.... but they haven't touched the Alternanthera.
And finally, one of my amanos had eggs when I got her, and now like 2+ weeks later she's still carrying them around. *shrug*