Here's Some Answers
The Revolt Risk is calcualted at the beginning of every month. Thus, if you have a 3% revolt risk, on the first of every month, the game runs the odds on a revolt in the province. Though you have a 97% chance of NOT getting a revolt, there's a 3% you WILL. Revolt risk can be reduced by promoting legal counsels, building manufactories, promoting mayors, changing your religious tolerance (if the province is of a different religion than the state), and by increasing stability.
The colonization/trading post chance of success percentage is PER COLONIST. So, for each colonist/trader you send, the percentage listed is the odds that the colonist/trader will successfully establish a colony/trading post. Generally, the percentage of success for these increases with each level of colonization you've got. So, it'll be easier (higher percent chance of success) to send a colonist to a Level 6 colony, and it'll be a lot harder (a lower percent chance of success) to send a colonist to establish a brand new colony.
I think those are the only percentages you asked about, but there's other problems, e-mail me...
cucm10@yahoo.com
Hope I helped.
The Black Adder