Iding small one branch frags accurately is pretty tough but here are my guesses
1. A microclados- small polyps between the exsert radial corallites are a giveaway.
2. hard to say for sure, structure looks a bit like A. latistella to my eyes
3. A. subulata, maybe secale
4. possibly A. saramentosa
Update after they grow a bit more for more accurate ideas.