You could have most corals with that much light.
Sponges would work, just make sure you understand their own specific requirements (no exposure to air etc)
Bubble corals would also work, just remember they are extremely aggressive and have 6 inch sweeper tentacles.
Yellow tail damsels are quite aggressive, and you may ahve problems having two of those and a clown. if it was me I'd get a blue/green chromis and a pair of clowns.
50 to 100w would be best for a heater.
The white dots are probably hydroids, don't worry there not a problem.