Yes. Median emissions intensity for electricity from combined-cycle natural gas plants, reported by the IPCC as of 2014, is 490 grams of CO2-equivalent per kilowatt hour. That compares with coal at 820 g/kWh and cofired coal/biomass at 740 g/kWh.

https://en.wikipedia.org/wiki/Life-cycle_greenhouse-gas_emis...

Yes. About half the CO2 as well as an order of magnitude less NOx not sure on other levels. I'm pretty sure much less CO. IIRC lower levels of byproduct is because LNG is a more pure hydrocarbon than Coal.

Yes. Natural gas plants drop emissions by 50-60% compared to a comparable coal plant.