Nope...five or six of the super Tuesday States have a 50% threshold that if any candidate achieves...they get all of the delegates. Up to 50% it is proportional, after that its winner take all.
The first full winner take all if on the 15th with FL and OH.
Yes, all the states are proportional. Some states have a threshold of 10%, some are 30% or whatever. In a multi candidate field, the odds of anyone achieving 50% are small.