Agree with captivereefs... the bubble/frogspawn/hammer corals all together in a 24g might be asking for trouble. I had a torch (same family as the hammer/frogspawn... Euphyllia) in a 46g that had to be taken back to the LFS
after 8 months or so because it just grew too big and was trying to kill off other corals. They're all beautiful corals, but I'd probably just choose one from that family for a 24g. I really like bubble corals, and they seem to be the least agressive of the bunch mentioned. I'd probably recommend one of those in a low flow area.
I think you'll love the yellow clown goby. I have one, and he's definitely the favorite of visitors when they check out the tank. Lots of personality, and it's all over the tank.
While I quarantine fish, I don't quarnatine corals. I just haven't wanted to invest to upgrade the lighting on my QT for that. Maybe I've just been lucky, but I haven't had any real issues with any corals that I've put in my tank. Ones that I've lost have had nothing to do with quarantine... or lack of.
Aiptasia should be obvious on a piece when you see it at the LFS
, so quarantine really won't help here. Plus, you can deal with that in your main tank without an issue. Bristleworms aren't a concern - I view them as free cleanup crew! When I buy coral, I look for any damaged sections or unhealthy areas. If there are any... I don't buy it. I also look for any unwanted algae. Oh... flatworms or other parasites should be obvious, but if you see any on other corals in the tank, be sure to check the one you're interested in really well.
Regarding long acclimation times, the heat issue is why I normally don't drip acclimate for more than an hour. The one time I did, I floated the small bucket that I was acclimating, in a larger bucket filled with water. That larger bucket had a heater in it so that the large bucket water stayed at 78 degrees. Kind of like floating the bag in water, but more complicated.