I like your rock work.
The BioCubes are fairly easy to maintain tanks. I started with a 14G years ago and still use it today (of course, I've since modded the poor tank to death).
Few things:
Definitely read through these threads when you have a chance: https://www.saltwaterfish.com/Two-Little-Fishies-CorAffix-2-oz-Cyanoacrylate-Adhesive_p_3244.html and https://forums.saltwaterfish.com/forum/thread/264597/a-list-of-extremely-helpful-threads-for-all-hobbyists
There is a ton of really good info in those links.
I'm assuming that a local fish store (LFS) told you to place the damsels in there to start a cycle? This works, there are better methods, but it will work nonetheless. Just know now, that you'll have to get rid of the damsels, should they survive the beginning of the cycle. Damsels are VERY aggressive, especially as they grow, and in a smaller tank, they'll beat on any other fish you try to add to the system.
If you have the basic 29G BioCube model, which comes with PC lighting, you're not going to be able to keep anemones. Anemones require high lighting to grow properly, and PC lighting won't cut it. If you have the HQI version (contains a metal halide lighting fixture), then you'll be able to keep anemones. In your size tank, I wouldn't recommend anything other than a small bubble tip anemone (BTA) or a mini carpet anemone. Anemones back a powerful sting, and stretch far, which can cause issues in nano tanks, because they'll sting other corals you try to place near them.
As for corals, start with easier corals such as mushrooms, palythoas and other soft corals. Some easier soft corals are Kenya Tree, Xenia and Green Star Polyps (GSP). All three of these are fast growers and often considered "weeds" because they can smother other corals. Depending on where you live, you might be able to find someone in a local reef club giving away these corals for free, or close to free, definitely worth looking into. As they start to grow too much for your liking, you too can start to remove them and sell them to others.
As for fish, are there any that have caught your eye thus far? There are TONS of possibilities, but ultimately, it's your tank. If it were mine, I'd probably do a pair of Ocellaris Clownfish, a Tail Spot Blenny, a Green Banded Goby, a McCosker's Fairy Wrasse (or similar fairy or flasher wrasse), a Clown Goby and a Black Cap Basslet (maybe)
Also, what do you have to testing your salinity and water parameters (ammonia, nitrite, nitrate, pH, etc)?