Generally when it comes to starfish, they're 1 of 2 things;
The starfish is reef safe, but has a specialized diet we're unable to manually regulate and isn't feasible to keep long term in anything but the largest tanks that might naturally replenish it in large quantities. Your fromias, sandsifters, etc fall in this category. Linkcias to a lesser extent but very fragile and specific still.
Or,
The starfish can be fed, but it will eat and destroy anything, it will basically bleach your rock of anything sessile (your coral) and if it is an option they would eat your fish if catchable sleeping/sick. Your chocolates, Red Knobby, Biscuits, etc are this. The chocolates in my sump for feeder purposes are given little neck clams to lessen them eating each other even.
Serpents and brittle starfish are very different from traditional sea stars (more mobile and not reliant on tube feet to move, scuttling around), and happen to be safer as they're scavengers, they'll eat the same stuff you feed the rest of the tank and have no interest in stuff growing on the rock. Serpents are safe, brittles its the green ones with a bad reputation for eating fish but the rest I never seen complaints about. In a 10 I'd recommend maybe one serpent, they're not huge but they do take up a bit of surface area at the bottom, most brittles get too big.
Microbrittles are already in your tank as hitchhikers, you just haven't seen them yet. They're as omnipresent in tanks as bristleworms, you'll sometimes see an arm extend out of rocks at night.
Feather/Basket Starfish don't even look at them, they're not starfish in a traditional sense, they're crinoids and they're a big customer trap, you can count the number of individuals that had one alive for a short peroid of time on one hand.
