I wouldn't add coral if your getting a puffer, if you did add coral i would try sps
first, In a 75 gallon you could add all the above as long as you get a dwarf puffer, and lion. I've seen 75G tanks with up to 7 moderately sized fish, if your going with a predator tank, i would not add any coral thats just IMO
, just make sure you watch your parameters and do a weekly 10% water change especially if your doing a predator tank due to the amount of waste they produce. You could possible add a small wrasse, or smaller tang as well. 75G are great starter predator tank. I would also add a skimmer to help with the waste. Hope this helps!