Here are the answers to your questions:
Question 1: The word with a positive connotation for "curious" is inquisitive.
Question 2: The word to describe a stubborn person in the most negative way is pig-headed.
Question 3: The correct denotation for the word "clumsy" is awkward.
Question 4: The word with the most positive connotation is beam.
Question 5: If you wanted to describe an honest person in a negative way, you would use the word blunt.