Splatoon 2 salmon run do you have to be in the same rank as your friends in order to play with them

Since I own the German version I don't know how it is called in English, but when you stand in front of the building where the Salmon Run is played, you will find a counter to the left of it. There you can pick up your prizes.

It is only the paycheck of the workers that influence how the difficulty is. Ex: If you are a Part-Timer then the rounds will be easier then if you were a Trainee. If you survive until the next round then the boss salmonoids will despawn. The difficulty between rounds is always the same unless a player messes it up.

Edit: The difficulty between round is random because of events Ex: One round is High tide, Round 2 is The Griller And round 3 is Cohock Charge.