What is the significance between Red & Blue & Blue & White lights on police vehicles?

There is no significance other than state law and local preference. In my state the law specifies that blue is for law enforcement vehicles. Red are for all other emergency vehicles. In some states, like CA and NY, police also use red. In my state some agencies will have blue and red lights. Since studies have shown red flashing lights are more visible during the day, but blue lights are more visible at night. Some will throw white lights in there just because it's a better visibility compromise.

Nothing special.

Some few states require an emergency vehicle to have a red light showing. One still requires at least one red light be on steady, not flashing. Legilatures have all kinds of strange ideas.

My old department was the first major to go with blue in the US. In most of Europe blue meant police, red meant ambulance, red & green was fire.

Blue and green can be seen better in smoke and fog.

Most police stations and temp HQs at scenes singal there existence for other responders to find easily by hanging a blue light

If you're gong to become a state trooper, then they'll teach you that stuff in the academy. Otherwise, you don't need to know.

And in another question, you claimed that you've been with the West Virginia State Patrol for 10 years. One of your statements is a LIE.