Source: Princeton Review

If the salary cap of the National Basketball Association were to be removed, the cost of running a championship team would increase by at least two million dollars or more.


If the salary cap of the National Basketball Association were to be removed, the cost of running a championship team would increase by at least two million dollars or more

Were the salary cap of the National Basketball Association to be removed, the cost of running a championship team would increase by at least two million dollars

Was the salary cap of the National Basketball Association to be removed, the cost of running a championship team would increase by at least two million dollars or more

If the salary cap of the National Basketball Association was removed, the cost of running a championship team would increase by at least two million dollars

Should the salary cap of the National Basketball Association be removed, the cost of running a championship team would increase by at least two million dollars or more

OA is B - is "to be" required and/or correct in this sentence? Is this a case of choosing the least worse option?

A: "at least" and "or more" are redundant.
C: same as A; in addition, "was" is the wrong form. Should say "were" - this needs the subjunctive mood because the sentence is conveying an if-then statement that isn't actually happening in fact. (eg, if I were rich, I would...)
D: same subjunctive mood issue
E: same redundancy issue

Yes, B sounds incredibly awkward... but it is also grammatically correct (yes, including the "to be" bit)! This is a classic case of: don't cross something off just because it's not the way you'd say it. As long as the grammar is right, it's fine.