Final answer:
The nurse should first address the stoma color, followed by the ostomy pouch seal.
Step-by-step explanation:
Part 1: The nurse should first address the stoma color because it appears dark purple with blistering on the skin around the stoma, which may indicate ischemia or necrosis. This is a concerning finding that requires immediate attention.
Part 2: The nurse should then address the ostomy pouch seal because it is slightly leaking, leading to the stool leakage. A secure pouch seal is important to prevent skin irritation and infection.