A child bride does not choose to be a child bride.

A child bride is a female child sold to a paedophile by human trafficker parents. There is no part of that transaction that is acceptable.

Minimum age. Otherwise, minors would be vulnerable to various forms of abuse.

There should be a national age limit. No one under 18 should be able to be married. Everyone should be advised to wait until 25. Childhood marriage has a strong link to divorce, abuse, lack of education, there is almost no good outcomes (most particularly for women) that results from childhood marriage. No one is actually 'mature enough'. That denies the biology of the brain. People used to marry young, because life expectancy was far more brief and maternal mortality was crazy high. This is no longer the case, there is no reason to subject children to something that can cripple their entire life.

I suppose I could make a strong moral argument here, but no one important will listen anyways.

So, a better argument ( one that might actually appeal to lawmakers ) is that it has the potential to drastically reduce taxable income because a child likely doesn't make as much as someone older who is in a higher tax bracket, and this would reduce the amount of taxable income when they file jointly.

The tax code is written such that the combined total is taxed somewhere in the middle, and this usually means a smaller sum is paid than if they filed separately.

If someone is making a lot of money per year that amount could greatly exceed the amount that a family would get as a deduction when they list the child as a Dependant.

There is no right answer to this. People are individuals, not computers to be programmed.

No. But there needs to be laws partaining to legal age of consent. There should also be mandatory sterilization for both sexes until such time as the individual proves to be psychologically and financially stable enough to raise a child.

Yes, there should be a minimum age, with the ability to petition the court for extreme exceptions.

May be worth discussing what marriage has to do with anything.

It used to a be a legal affair to ensure land rights, alliances etc. Then it became a God thing which seems irrational. What is it’s function in C21st?

Ascertain that, then you can determine age limits and other associated circumstances.