POSSIBLY. It may constipate you.
Yes. This is a common combination.
Similar to morphine. Codiene is classed as an opiate. The parent drug of this class is morphine. The side effects are similar for all drugs in the class and include itching, nausea, vomiting, euphoria, drowsiness, dry mouth, depression, urinary retention (difficulty urinating) and constipation. A potentially serious side effect is respiratory depression or a slowing of respirations leading to respiratory arrest.
Yes. Yes you can.
Yes. They can be taken together.
Aleve/tylenol. Yes you can.