1. Minimum length of service to upgrade?
No minimum length as such, but it is stated in our CU guidance material that you need two "good" or better grades in your last recurrant simulator sessions. That's at least 12 months.
2. Minimum flying experience to upgrade?
You have to have the following minima before you start CU. Not every single person is exactly on these minima, some have prior experience in other companys, but many do start the CU with these:
• 2900 hrs total time
• 1500 hrs on JAR 25 type aircraft
• 500 hrs on the B737-800
You also need one winter of winter Ops within the company, or one winter in a JAR-OPS company on type.
3. Does swinging propellors count, or must it be all jet time?
Prop time counts but subject to the conditions in point 2.
4. Upgrade aircraft type?
Just the one type. The 737-800
5. Current actual years to upgrade? (state "unknown" if no current training)
Was as low as 3 years. 3.5 seems to be more accurate just at the moment. However many deliveries still planned so the pace might pick up again in the spring.
5. Low cost carrier or full service?
Neither. Low
Fares 
6. Which continent?
Europe.
7. Airline trading name if not to much to ask?
Ryanair.