Can men wear below two gram gold?

I don't see why you think the weight of the gold would be an issue; two grams or l0, ring or necklace or bracelet. The more the gold weighs, the more expensive it is, if that is what you mean.

No, I don't think it matters.

No it does not, drinking and earning money as interest or lending money to someone on heavy interest is haram. Wearing gold is not haram, kings and royals always use to wear gold.