No, not all white people believed in slavery. There were white individuals who were against slavery and fought for its abolition. Additionally, there were free African Americans and indigenous peoples who also opposed slavery.

The cast of White Slavery - 1991 includes: Boss Kingpin

Yes slavery has no ethnic boundaries.

There are no records kept of someone who was the first white to be against slavery. There is no way of knowing.

The southern white people wanted slavery forever because they wanted more unfair laboring to the white farmers.