Answer to Question 1
The predominant bright red is the emission from ionized hydrogen, heated to over 3,000 K by the ultraviolet radiation of imbedded O and B type stars. Other colors come from emission lines of other atoms. Some blue light will be scattered by cooler dust particles as well.
Answer to Question 2
Hydrogen. On Earth hydrogen is a gas because of the pressure and temperature in our atmosphere. On Jupiter and Saturn, it can be liquid and have the properties of a metal because of the much higher temperatures and pressures.