Exactly.Working with marine environments. It's a major factor when selecting fasteners. You don't want the fastener corroding sacrificially to the plate. Ya know?

You can measure the voltage. It's tougher to predict the damage or the location of the damage. All you'd really be able to decern is roughly how many atoms are moving around

Short answer: Yes.Long answer: Galvanic corrosion takes place when any two metals come in contact with each other. The severity depends on how cathodic/anodic they are in relation to each other. How aggressive the reaction is depends on how different their electrochemistry is, with the more anodic metal losing material or corroding.Steel is also a very broad category. Where a low alloy steel might corrode in contact with aluminum bronze, a bimetallic couple with stainless steel would cause the aluminum bronze to corrode.
Search for "galvanic series" charts to see where your materials end up to get a general idea of how they would react