Re: Q2.
Most jet aircraft will require ignition ON for take-off, regardless of flight conditions (e.g B737) as this provides a measure of flame-out protection. If there is standing water it will always (in my experience of jet ops) be ON.
Engine Anti Ice will be required below a certain OAT if moisture is present - again, for B737 I think this figure is usually +10C (certainly on the -200) although as stated by other posters this may vary by type. Given that the B737 seems to be the "aeroplane of choice" for the JAA, I would say ON with +8C and that RVR/standing water.
Airframe Anti/De-Ice must be treated as a separate issue from Engine Anti-Ice. Bleed air type airframe anti-ice systems are usually used to DE-ICE and so are not used unless ice has already built up on the airframe.
Prior to take-off, airframe de-icing will be carried out using chemical de-icer and the crew will plan to be airborne before the end of the holdover time (which varies according to met conditions and type of fluid used). If such chemical de-ice is not availanble, the aeroplanes airframe de-icing system may (depending upon type) be used but the effect on performance will have to be calculated. For example, using airframe de-ice on a B737-200 will typically reduce MTOW by about 3,500kg!
Hope that helps.