Limitation on Hokkaido Rail Pass?

1. If I have Hokkaido Rail Pass, do I have to pay additional for reserve seat?
2. Does the pass cover the use of 3 subway lines within Sapporo?
3. Can I use this pass for travel from CTS airport to Sapporo?

Thank you.

1. If I have Hokkaido Rail Pass, do I have to pay additional for reserve seat?

No.

2. Does the pass cover the use of 3 subway lines within Sapporo?

No, they are not JR trains.

3. Can I use this pass for travel from CTS airport to Sapporo?

Yes, on the JR trains between the airport and Sapporo.

1. If I have Hokkaido Rail Pass, do I have to pay additional for reserve seat?
2. Does the pass cover the use of 3 subway lines within Sapporo?
3. Can I use this pass for travel from CTS airport to Sapporo?

1) No
2) No JR trains only
3) Looks you can as Shinchitosekuko Station to Sapporo Station is a JR line

Then it depends how many days and travels to pick which passes as shown here http://www.japan-guide.com/e/e2361_01.html

Hope this help!!!

Have Fun!!!