Loans

Is there a way to offer loans directly to a country or do they all have to go through the open market?

You can only offer loans on the open market.
Offering loans directly wouldn't have any real meaning anyway because the interest rates you offer can not be modified

How do you change the term of the loan and the interest rates?

You can set the term in the loan page, but the interest rate is fixed.

Yes. Interest rate changes were removed a long time ago, because that feature was being abused.
Some clever players were amassing enormous wealth by making dummy accounts and loaning those accounts money with maximum interest rates.