Of course they may NOT be separate plants, it's hard for us to tell what's lurking beyond the top mulch. But even IF there are 3 cuttings there, personally I like the present multi-stemmed look better than I would 3 separately planted. I think the advantage of that, outweighs any negatives. Although most ficus are incredibly tough, you may indeed upset things by seeking to split them - at least set them back a bit as I dare say their root systems would be mingled by now. With so many branches, it will allow any occasional leaf loss to go less noticed and the plant to be turned to allow more even growth. One pot that has to be gradually increased is better than 3 separate ones all to be tended especially if floor space is limited - what really keeps them growing is light. The roots have a dual purpose - stabilising a plant as well as providing a feeding system. So, if you keep up nutrients during growing phases, there is no reason why all three plants would not remain healthy. On the other hand, a more restricted root area (as I say, given that you will probably have to pot on occasionally proportionate to the height of the plants) may tend to keep them more manageable height and stop them bolting. If they do not naturally branch later, you can always cut one and try to force new buds, without destroying the total effect of the plant. Anyway that's my 2cs

Haworthia Attenuata. My opinion it's a bit off focus but looks good, you could wait for it to fill in more is an option even though I would remove one of the smaller

don't separate, there is no need for now , seedlings are often grown together. let them grow 1st year like this, then when they slow down (and most likely drop all leaves) in winter (dry season) , you can separate in early spring. you get slightly cooler temps in winter in so-cal too? when soil temp is dropping to 65F and below they slow down and need to be kept on a dry side. but if they drop all leaves then stop watering for a month and then separate/repot. mature tubers can be dry for sev months, but with young tubers it is recommended to restart them after a month, or they might dry out too much and die/rot. seedlings get easily water-logged: absorb too much water and then you'll see darker streaks on leaves and gutation (drops from the tip of the leaf) - and it can lead to necrosis of the leaf (yellows in patches and then leaf dies). so it's not a bad idea to have 2 seedlings together in a very small pot as it'll remain drier this way.

They usually are three separate trees...the typical way of doing this is to stick three saplings in the same pot. This looks awesome when the tree is young. No idea what it does in the long run, but probably doesn't maximize the trees life expectancy. I've seen old single specimens of River Birch...they look fine. They might look kind of sad and lonely when the tree is small. If you ARE going to separate them, I'd do it now. Not the ideal time of year, but the alternative is planting them now, digging them up later, and traumatizing them twice. You may want to pull apart circling roots anyway on a clearance tree. If they are potted them out of the pot and them in a bucket of water briefly to soften the roots and make it easier to pull them apart. Then I dump the bucket of water th the planting hole(s?) and wait for it to drain. Maybe partially shade them with a tarp when the real heat hit?