I agree, frequent small water changes are best in smaller tanks for sure. I have a 220gallon reef, a 14gallon nano reef and a 2gallon pico reef. Easiest tank to manage is the big one. LOL. The smaller the tank the more difficult it is to maintain water quality. Also top off is VERY important. You MUST be diligent about top offs because even a little evaporation will have the salinity skyrocketing. I do not have auto top offs on my little tanks but I top them off twice a day at least. In my 14g I have a pair of Wyoming white clowns, a couple of hermits, a pompom crab, lots of corals, and various snails. I had a jawfish in there but the clowns never let it leave the burrow so I moved it to the big tank.
In my opinion:
Serpent stars get way too big and can eat fish, plus starfish need very stable water conditions. One of the most important things for success with a sea star is controlling salinity which as I mentioned before is difficult in these little tanks. I have a Linkia in my large reef and he has done well for a couple of years, but water is super stable. Even he is too big for a nano though.
Anemone, I have a tube anemone in my big tank, "she" is gorgeous, but she is almost 18 inches in diameter now. I wouldn't recommend one in a nano, they also get biggest at night so whatever size you think it is, it is at least twice that at night. It is non photosynthetic and even the well fed ones will take the opportunity to catch your fish. It is not ethical to keep fish in a small tank with one of these because they are bound to fall prey to those stinging tenticles.
I also have a bubbletip anemone in the big tank with 2 happy clowns in it. A small one would be ok in an established nano, but wait at least 6 months or even a year before you add a nem, they need mature systems. They will also wander, into powerheads, the overflow grate, and when they die they usually nuke the tank and kill everything, especially in small tanks. If you want to have coral down the line you should know a wandering anemone will sting and kill coral so use caution when adding one to your tank. Most anemones are photosynthetic and carnivorous so you must have high lighting to meet their needs. Lighting is important for the coral as well. Once your tank is mature you may want to consider a rock flower anemone, they can be very beautiful.
One or two small fish should be fine, if you get a pair of clowns expect them to be territorial and 10 g is not a lot of territory so other fish may be bullied pretty bad. Avoid damsels unless you want just the one fish because they are territorial too and will want the entire tank to themselves. There are a lot of small peaceful fish perfect for nanos, but choose wisely bc when you are only stocking a few fish, you want fish you will get to see, not hiders. The best resource for which fish are suitable for nanos is the nano fish section at liveaquaria.com. Not saying buy from them, I never have, but the list and tank requirements is very accurate.
I love the challenge of the nano tank. I like it better than the big tank because I can look in and see their whole world. You won't regret it if you slow down and do it right and stock wisely. Good luck. I am far from an expert, but feel free to PM me if you have a question!