Maaaaan. I thought I could answer anything but I haven't been in the freeform enough to be certain I am answering correctly.
I will try and answer the site level questions....well, because it makes sense that way. The roleplaying portions will come from those with more experience then I. I may stick my foot in my mouth too, so if anybody contradicts me....go with the contradiction.
Most of your answers will have to be answered per game/thread. Each game started will sort of have their own unspoken rules, but should be pretty easy to gather from the other posts. Some games will allow (or require) more powerful creatures/elements/etc., Many people will simply do an OOC question directly in the thread to OK what they want to do (or ask specific questions about the thread). We are real loose so as long as you aren't spamming and flaming they will be happy to answer any thread specific questions.
Freeform really is freeform. With a few exceptions, each game is a growing story that each person adds to whatever they think is appropriate. If there is somebody guiding the story, they will let you know.
Don't like chat speak that much. There are others that *really* don't like it. Better use full sentences and stay away from it if you can. Hopefully if there are slips they won't be too harsh on you....
Stupid noises are fine....as long as there is content associated with it

more answers are sure to come....