It's a Wiener (you had a typo there) process and the name refers to a sausage or an inhabitants of the Austrian capital in German. So I'd pronounce it VEEner in German. Of course, if the guy was American then idk. His parents were German and Polish though.

Jensen was Danish so it's probably pronounced similar to German (?) so it'd be YENsen.

Fourier is Foo-r(i)EH in regular French.