a) you can elect to make your IRA contribution non-deductible, in which case it doesn't matter what your MAGI is.
b) if you wish to convert tax free to Roth, your entire value of all your IRAs must be no more than your basis which is the non-deductible part,
Otherwise it cannot be 100% tax free because a Traditional IRA distribution or conversion always has a basis fractional part and a taxable fractional part as calculated on Form 8606.
@VAer
