I'm going to answer as far as I know, which may be errant. Correct me as I go along, please....
1. What responsibilities/roles does a godparent have? Do they simply answer questions re: religion or do they help us with all of life's question from a Christian perspective?
All aspects. I think this is what makes their role so important - they are there to help discern God's will, pray with the godchild, help the godchild during spiritual ruts, all the days of their life.
2. Does a godparent stay with you your whole life or just during the catechumenate/ early post-baptism/chrismation period?
It is my understanding that they help you during the Great Judgment, so I assume it's important to be in lifelong contact.
3. What are the requirements to becomming a godparent? Should you make your intentions/wishes known to the priest?
A member "in good standing" according to the minimums of your jurisdiction. The priest must approve the selection of Godparents.
4. Is it imperative or a good idea that the godparent be older than the new Christian?
I'd say go for someone more mature than the candidate. Maturity is not always measured by years, but age and experience are usually good benchmarkers.
8. Is being a godparent serious or simply ceremonial?
Very very serious.
9. Is th whole godparent issue simply an antiquated idea that we don't really need anymore?
Theologically, I don't believe that's possible (see #2). Practically, how can a baby say "I denounce Satan..."?