Derive the Year from another field

I don't really understand your second question as to how it relates to the first question. They seem unrelated. But I will take the liberty of simplifying your current formula because it's written in an Excel type manner which is needlessly complicated with parentheses 

IF(
[Request] = "Add New Resource" and [New Employee Type] =  "FTE",
[PRM Level - New FTE Monthly Estimate] * [First Year Duration],

[Request] = "Add New Resource" and [New Employee Type] =  "Contractor",
[Contractor Monthly Estimate] * [First Year Duration],

[Request] = "Include Existing Contractor - No Conversion",
[Contractor Monthly Estimate] * [First Year Duration],

[Request] = "Include Existing FTE - Continue or Shift Project",
[FTE PID - Level Estimate - Monthly Estimate] * [First Year Duration],

[Request] = "Add New Contractor + Add New FTE for Conversion",
[Contractor Monthly Estimate] * [First Year Duration],

[Request] = "Include Existing Contractor + Add NEW FTE for Conversion",
[Contractor Monthly Estimate] * [First Year Duration],

[Request] = "New FTE (Related to Conversion)",
[PRM Level - New FTE Monthly Estimate] * [First Year Duration])

as for the first question.

The formula for [Year 1] would be 

Year([BUSINESS CASE START DATE])

Then the formula for [Year 2] would be [Year 1] + 1.

etc for the rest of Years 3,  4 and 5.