If you have a well vented hood, a fan blowing air into the hood, and a relatively cool house you will not have any trouble keeping the tank cool.
As for livestock:
Basslets, Hawkfish, Gobies, Blennies, Dwarf Angels, Snowflake Eel, etc.
Candycane, Trumpet, Brain, Favia, Hammer, Torch, Frogspawn, Montipora, Stylophora, Leathers, etc. (Tree coral is a Softy, not a SPS)
As for number, you just have to see how crowded the tank gets. Hawkfish, blennies, gobies, basslets, and eels all perch/hide so that they don't really get in the way for free swimmers, such as clownfish. So while they do take up space, their should be less tension.