You're perhaps not recognising the particular verb here, one of several different uses of have:
- have to means be obliged to, or must
So would have had to means would have been obliged to.
These are all variants on the conditional mood. As a general rule, the "would" statement is known as the "conditional perfect", and can only be used in the clause that describes the consequence, not the one that sets up the condition (i.e. "If I would" is always incorrect).
A short breakdown of the examples, to the best of my knowledge:
1 is incorrect due to mixed tenses. "I would do" is present tense; "had I been" is past.
2 is correct: the tenses match (both past). The removal of "if" and the swapping of the order to "had I" in the second clause is a conditional inversion.
3 is also correct: Here, "were" is being used in a form known as the "present unreal conditional".
4: Correct; "were" is also used for the past unreal conditional (so again, the tenses match)
5&6: both incorrect; "would I be him" would only work in the form of a question, and not as part of the conditional statement: "If I changed into his clothes, would I be him?"
7&8: Same as in 5&6, only framed in the past tense (so the start would be "If I had changed[...]")
9-12 are all incorrect as the conditional perfect ("would[...]") cannot be used in an "if" clause, as mentioned at the start.
Best Answer
That's right. By using the conditional with would, the writer is saying that even if you went with the first option, you would still have to pay the taxes. The implication is that this second option is better because you get its benefits (the citizenship within 3 years) since no matter which you choose you would still have to pay the taxes.
In explaining the "taxes you would have had to pay anyway" you could say "taxes you would have had to pay anyway had you chosen not to move to Russia". It implies that in the current tense we're talking about the second option as if we've already chosen it, and then considering what would have happened if we chose the first option.