Calculate the following using a principal amount of $686884, an initial interest rate of 3.59%.

1. Initial fortnightly payment of a 20-year mortgage using the PVA formula.

2. Fortnightly payment in Year 5 - 8 if the interest rate is increased by 2.5% after 4 years using the PVA formula.

3. Fortnightly payment from Year 9 onwards if the interest rate is further increased by 1.5% after 8 years using the PVA formula.

4. Effective annual interest rate(s) for Year 1-4, Year 5-8, and Year 9-20.

5. Average Effective annual interest rate of this mortgage.